LibGUI+Everywhere: Use fallible Window::set_main_widget() everywhere :^)

Rip that bandaid off!

This does the following, in one big, awkward jump:
- Replace all uses of `set_main_widget<Foo>()` with the `try` version.
- Remove `set_main_widget<Foo>()`.
- Rename the `try` version to just be `set_main_widget` because it's now
  the only one.

The majority of places that call `set_main_widget<Foo>()` are inside
constructors, so this unfortunately gives us a big batch of new
`release_value_but_fixme_should_propagate_errors()` calls.

16 files changed, 91 insertions, 99 deletions

diff --git a/Userland/Libraries/LibGUI/AboutDialog.cpp b/Userland/Libraries/LibGUI/AboutDialog.cpp
index d75d3e0cec..692736e7ae 100644
--- a/Userland/Libraries/LibGUI/AboutDialog.cpp
+++ b/Userland/Libraries/LibGUI/AboutDialog.cpp
@@ -30,15 +30,15 @@ AboutDialog::AboutDialog(StringView name, StringView version, Gfx::Bitmap const*
     if (parent_window)
         set_icon(parent_window->icon());
 
-    auto& widget = set_main_widget<Widget>();
-    widget.set_fill_with_background_color(true);
-    widget.set_layout<VerticalBoxLayout>();
-    widget.layout()->set_spacing(0);
+    auto widget = set_main_widget<Widget>().release_value_but_fixme_should_propagate_errors();
+    widget->set_fill_with_background_color(true);
+    widget->set_layout<VerticalBoxLayout>();
+    widget->layout()->set_spacing(0);
 
-    auto& banner_image = widget.add<GUI::ImageWidget>();
+    auto& banner_image = widget->add<GUI::ImageWidget>();
     banner_image.load_from_file("/res/graphics/brand-banner.png"sv);
 
-    auto& content_container = widget.add<Widget>();
+    auto& content_container = widget->add<Widget>();
     content_container.set_layout<HorizontalBoxLayout>();
 
     auto& left_container = content_container.add<Widget>();
diff --git a/Userland/Libraries/LibGUI/Application.cpp b/Userland/Libraries/LibGUI/Application.cpp
index 1d78929107..9b38932d66 100644
--- a/Userland/Libraries/LibGUI/Application.cpp
+++ b/Userland/Libraries/LibGUI/Application.cpp
@@ -44,7 +44,7 @@ private:
     {
         set_window_type(WindowType::Tooltip);
         set_obey_widget_min_size(false);
-        m_label = set_main_widget<Label>();
+        m_label = set_main_widget<Label>().release_value_but_fixme_should_propagate_errors();
         m_label->set_background_role(Gfx::ColorRole::Tooltip);
         m_label->set_foreground_role(Gfx::ColorRole::TooltipText);
         m_label->set_fill_with_background_color(true);
diff --git a/Userland/Libraries/LibGUI/AutocompleteProvider.cpp b/Userland/Libraries/LibGUI/AutocompleteProvider.cpp
index b71fb4fc1b..fb450d9ae7 100644
--- a/Userland/Libraries/LibGUI/AutocompleteProvider.cpp
+++ b/Userland/Libraries/LibGUI/AutocompleteProvider.cpp
@@ -92,11 +92,11 @@ AutocompleteBox::AutocompleteBox(TextEditor& editor)
     m_popup_window->set_obey_widget_min_size(false);
     m_popup_window->set_rect(0, 0, 175, 25);
 
-    auto& main_widget = m_popup_window->set_main_widget<GUI::Widget>();
-    main_widget.set_fill_with_background_color(true);
-    main_widget.set_layout<GUI::VerticalBoxLayout>();
+    auto main_widget = m_popup_window->set_main_widget<GUI::Widget>().release_value_but_fixme_should_propagate_errors();
+    main_widget->set_fill_with_background_color(true);
+    main_widget->set_layout<GUI::VerticalBoxLayout>();
 
-    m_suggestion_view = main_widget.add<GUI::TableView>();
+    m_suggestion_view = main_widget->add<GUI::TableView>();
     m_suggestion_view->set_frame_shadow(Gfx::FrameShadow::Plain);
     m_suggestion_view->set_frame_thickness(1);
     m_suggestion_view->set_column_headers_visible(false);
@@ -109,7 +109,7 @@ AutocompleteBox::AutocompleteBox(TextEditor& editor)
         apply_suggestion();
     };
 
-    m_no_suggestions_view = main_widget.add<GUI::Label>("No suggestions");
+    m_no_suggestions_view = main_widget->add<GUI::Label>("No suggestions");
 }
 
 void AutocompleteBox::update_suggestions(Vector<CodeComprehension::AutocompleteResultEntry>&& suggestions)
diff --git a/Userland/Libraries/LibGUI/ColorPicker.cpp b/Userland/Libraries/LibGUI/ColorPicker.cpp
index f8a640fdcc..7dac2fe557 100644
--- a/Userland/Libraries/LibGUI/ColorPicker.cpp
+++ b/Userland/Libraries/LibGUI/ColorPicker.cpp
@@ -206,12 +206,12 @@ void ColorPicker::set_color_has_alpha_channel(bool has_alpha)
 
 void ColorPicker::build_ui()
 {
-    auto& root_container = set_main_widget<Widget>();
-    root_container.set_layout<VerticalBoxLayout>();
-    root_container.layout()->set_margins(4);
-    root_container.set_fill_with_background_color(true);
+    auto root_container = set_main_widget<Widget>().release_value_but_fixme_should_propagate_errors();
+    root_container->set_layout<VerticalBoxLayout>();
+    root_container->layout()->set_margins(4);
+    root_container->set_fill_with_background_color(true);
 
-    auto& tab_widget = root_container.add<GUI::TabWidget>();
+    auto& tab_widget = root_container->add<GUI::TabWidget>();
 
     auto& tab_palette = tab_widget.add_tab<Widget>("Palette");
     tab_palette.set_layout<VerticalBoxLayout>();
@@ -227,7 +227,7 @@ void ColorPicker::build_ui()
 
     build_ui_custom(tab_custom_color);
 
-    auto& button_container = root_container.add<Widget>();
+    auto& button_container = root_container->add<Widget>();
     button_container.set_preferred_height(GUI::SpecialDimension::Fit);
     button_container.set_layout<HorizontalBoxLayout>();
     button_container.layout()->set_spacing(4);
diff --git a/Userland/Libraries/LibGUI/ComboBox.cpp b/Userland/Libraries/LibGUI/ComboBox.cpp
index 7d95f2e26b..88eba5a0de 100644
--- a/Userland/Libraries/LibGUI/ComboBox.cpp
+++ b/Userland/Libraries/LibGUI/ComboBox.cpp
@@ -116,7 +116,7 @@ ComboBox::ComboBox()
     m_list_window = add<Window>(window());
     m_list_window->set_window_type(GUI::WindowType::Popup);
 
-    m_list_view = m_list_window->set_main_widget<ListView>();
+    m_list_view = m_list_window->set_main_widget<ListView>().release_value_but_fixme_should_propagate_errors();
     m_list_view->set_should_hide_unnecessary_scrollbars(true);
     m_list_view->set_alternating_row_colors(false);
     m_list_view->set_hover_highlighting(true);
diff --git a/Userland/Libraries/LibGUI/CommandPalette.cpp b/Userland/Libraries/LibGUI/CommandPalette.cpp
index 52a4501d69..2d2ad31f7d 100644
--- a/Userland/Libraries/LibGUI/CommandPalette.cpp
+++ b/Userland/Libraries/LibGUI/CommandPalette.cpp
@@ -182,15 +182,15 @@ CommandPalette::CommandPalette(GUI::Window& parent_window, ScreenPosition screen
 
     collect_actions(parent_window);
 
-    auto& main_widget = set_main_widget<GUI::Frame>();
-    main_widget.set_frame_shape(Gfx::FrameShape::Window);
-    main_widget.set_fill_with_background_color(true);
+    auto main_widget = set_main_widget<GUI::Frame>().release_value_but_fixme_should_propagate_errors();
+    main_widget->set_frame_shape(Gfx::FrameShape::Window);
+    main_widget->set_fill_with_background_color(true);
 
-    auto& layout = main_widget.set_layout<GUI::VerticalBoxLayout>();
+    auto& layout = main_widget->set_layout<GUI::VerticalBoxLayout>();
     layout.set_margins(4);
 
-    m_text_box = main_widget.add<GUI::TextBox>();
-    m_table_view = main_widget.add<GUI::TableView>();
+    m_text_box = main_widget->add<GUI::TextBox>();
+    m_table_view = main_widget->add<GUI::TableView>();
     m_model = adopt_ref(*new ActionModel(m_actions));
     m_table_view->set_column_headers_visible(false);
 
diff --git a/Userland/Libraries/LibGUI/EmojiInputDialog.cpp b/Userland/Libraries/LibGUI/EmojiInputDialog.cpp
index 1cc0dff127..f4d99562d5 100644
--- a/Userland/Libraries/LibGUI/EmojiInputDialog.cpp
+++ b/Userland/Libraries/LibGUI/EmojiInputDialog.cpp
@@ -92,8 +92,8 @@ EmojiInputDialog::EmojiInputDialog(Window* parent_window)
     : Dialog(parent_window)
     , m_category_action_group(make<ActionGroup>())
 {
-    auto& main_widget = set_main_widget<Frame>();
-    if (!main_widget.load_from_gml(emoji_input_dialog_gml))
+    auto main_widget = set_main_widget<Frame>().release_value_but_fixme_should_propagate_errors();
+    if (!main_widget->load_from_gml(emoji_input_dialog_gml))
         VERIFY_NOT_REACHED();
 
     set_window_type(GUI::WindowType::Popup);
@@ -101,10 +101,10 @@ EmojiInputDialog::EmojiInputDialog(Window* parent_window)
     set_blocks_emoji_input(true);
     resize(400, 300);
 
-    auto& scrollable_container = *main_widget.find_descendant_of_type_named<GUI::ScrollableContainerWidget>("scrollable_container"sv);
-    m_search_box = main_widget.find_descendant_of_type_named<GUI::TextBox>("search_box"sv);
-    m_toolbar = main_widget.find_descendant_of_type_named<GUI::Toolbar>("toolbar"sv);
-    m_emojis_widget = main_widget.find_descendant_of_type_named<GUI::Widget>("emojis"sv);
+    auto& scrollable_container = *main_widget->find_descendant_of_type_named<GUI::ScrollableContainerWidget>("scrollable_container"sv);
+    m_search_box = main_widget->find_descendant_of_type_named<GUI::TextBox>("search_box"sv);
+    m_toolbar = main_widget->find_descendant_of_type_named<GUI::Toolbar>("toolbar"sv);
+    m_emojis_widget = main_widget->find_descendant_of_type_named<GUI::Widget>("emojis"sv);
     m_emojis = supported_emoji();
 
     m_category_action_group->set_exclusive(true);
diff --git a/Userland/Libraries/LibGUI/FilePicker.cpp b/Userland/Libraries/LibGUI/FilePicker.cpp
index 0998ecdf79..93cbc3d2d8 100644
--- a/Userland/Libraries/LibGUI/FilePicker.cpp
+++ b/Userland/Libraries/LibGUI/FilePicker.cpp
@@ -84,16 +84,16 @@ FilePicker::FilePicker(Window* parent_window, Mode mode, StringView filename, St
     }
     resize(560, 320);
 
-    auto& widget = set_main_widget<GUI::Widget>();
-    if (!widget.load_from_gml(file_picker_dialog_gml))
+    auto widget = set_main_widget<GUI::Widget>().release_value_but_fixme_should_propagate_errors();
+    if (!widget->load_from_gml(file_picker_dialog_gml))
         VERIFY_NOT_REACHED();
 
-    auto& toolbar = *widget.find_descendant_of_type_named<GUI::Toolbar>("toolbar");
+    auto& toolbar = *widget->find_descendant_of_type_named<GUI::Toolbar>("toolbar");
 
-    m_location_textbox = *widget.find_descendant_of_type_named<GUI::TextBox>("location_textbox");
+    m_location_textbox = *widget->find_descendant_of_type_named<GUI::TextBox>("location_textbox");
     m_location_textbox->set_text(path);
 
-    m_view = *widget.find_descendant_of_type_named<GUI::MultiView>("view");
+    m_view = *widget->find_descendant_of_type_named<GUI::MultiView>("view");
     m_view->set_selection_mode(m_mode == Mode::OpenMultiple ? GUI::AbstractView::SelectionMode::MultiSelection : GUI::AbstractView::SelectionMode::SingleSelection);
     m_view->set_model(MUST(SortingProxyModel::create(*m_model)));
     m_view->set_model_column(FileSystemModel::Column::Name);
@@ -150,7 +150,7 @@ FilePicker::FilePicker(Window* parent_window, Mode mode, StringView filename, St
     toolbar.add_action(m_view->view_as_table_action());
     toolbar.add_action(m_view->view_as_columns_action());
 
-    m_filename_textbox = *widget.find_descendant_of_type_named<GUI::TextBox>("filename_textbox");
+    m_filename_textbox = *widget->find_descendant_of_type_named<GUI::TextBox>("filename_textbox");
     m_filename_textbox->set_focus(true);
     if (m_mode == Mode::Save) {
         LexicalPath lexical_filename { filename };
@@ -183,14 +183,14 @@ FilePicker::FilePicker(Window* parent_window, Mode mode, StringView filename, St
         }
     };
 
-    auto& ok_button = *widget.find_descendant_of_type_named<GUI::Button>("ok_button");
+    auto& ok_button = *widget->find_descendant_of_type_named<GUI::Button>("ok_button");
     ok_button.set_text(ok_button_name(m_mode));
     ok_button.on_click = [this](auto) {
         on_file_return();
     };
     ok_button.set_enabled(m_mode == Mode::OpenFolder || !m_filename_textbox->text().is_empty());
 
-    auto& cancel_button = *widget.find_descendant_of_type_named<GUI::Button>("cancel_button");
+    auto& cancel_button = *widget->find_descendant_of_type_named<GUI::Button>("cancel_button");
     cancel_button.set_text("Cancel");
     cancel_button.on_click = [this](auto) {
         done(ExecResult::Cancel);
@@ -237,7 +237,7 @@ FilePicker::FilePicker(Window* parent_window, Mode mode, StringView filename, St
         m_view->view_as_columns_action().set_enabled(false);
     };
 
-    auto& common_locations_tray = *widget.find_descendant_of_type_named<GUI::Tray>("common_locations_tray");
+    auto& common_locations_tray = *widget->find_descendant_of_type_named<GUI::Tray>("common_locations_tray");
     m_model->on_complete = [&] {
         m_view->set_active_widget(&m_view->current_view());
         for (auto& location_button : m_common_location_buttons)
diff --git a/Userland/Libraries/LibGUI/FontPicker.cpp b/Userland/Libraries/LibGUI/FontPicker.cpp
index 78479bba22..0ba0b36600 100644
--- a/Userland/Libraries/LibGUI/FontPicker.cpp
+++ b/Userland/Libraries/LibGUI/FontPicker.cpp
@@ -26,26 +26,26 @@ FontPicker::FontPicker(Window* parent_window, Gfx::Font const* current_font, boo
     resize(430, 280);
     set_icon(Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-font-editor.png"sv).release_value_but_fixme_should_propagate_errors());
 
-    auto& widget = set_main_widget<GUI::Widget>();
-    if (!widget.load_from_gml(font_picker_dialog_gml))
+    auto widget = set_main_widget<GUI::Widget>().release_value_but_fixme_should_propagate_errors();
+    if (!widget->load_from_gml(font_picker_dialog_gml))
         VERIFY_NOT_REACHED();
 
-    m_family_list_view = *widget.find_descendant_of_type_named<ListView>("family_list_view");
+    m_family_list_view = *widget->find_descendant_of_type_named<ListView>("family_list_view");
     m_family_list_view->set_model(ItemListModel<DeprecatedString>::create(m_families));
     m_family_list_view->horizontal_scrollbar().set_visible(false);
 
-    m_variant_list_view = *widget.find_descendant_of_type_named<ListView>("variant_list_view");
+    m_variant_list_view = *widget->find_descendant_of_type_named<ListView>("variant_list_view");
     m_variant_list_view->set_model(ItemListModel<DeprecatedString>::create(m_variants));
     m_variant_list_view->horizontal_scrollbar().set_visible(false);
 
-    m_size_spin_box = *widget.find_descendant_of_type_named<SpinBox>("size_spin_box");
+    m_size_spin_box = *widget->find_descendant_of_type_named<SpinBox>("size_spin_box");
     m_size_spin_box->set_range(1, 255);
 
-    m_size_list_view = *widget.find_descendant_of_type_named<ListView>("size_list_view");
+    m_size_list_view = *widget->find_descendant_of_type_named<ListView>("size_list_view");
     m_size_list_view->set_model(ItemListModel<int>::create(m_sizes));
     m_size_list_view->horizontal_scrollbar().set_visible(false);
 
-    m_sample_text_label = *widget.find_descendant_of_type_named<Label>("sample_text_label");
+    m_sample_text_label = *widget->find_descendant_of_type_named<Label>("sample_text_label");
 
     m_families.clear();
     Gfx::FontDatabase::the().for_each_typeface([&](auto& typeface) {
@@ -157,13 +157,13 @@ FontPicker::FontPicker(Window* parent_window, Gfx::Font const* current_font, boo
         update_font();
     };
 
-    auto& ok_button = *widget.find_descendant_of_type_named<GUI::Button>("ok_button");
+    auto& ok_button = *widget->find_descendant_of_type_named<GUI::Button>("ok_button");
     ok_button.on_click = [this](auto) {
         done(ExecResult::OK);
     };
     ok_button.set_default(true);
 
-    auto& cancel_button = *widget.find_descendant_of_type_named<GUI::Button>("cancel_button");
+    auto& cancel_button = *widget->find_descendant_of_type_named<GUI::Button>("cancel_button");
     cancel_button.on_click = [this](auto) {
         done(ExecResult::Cancel);
     };
diff --git a/Userland/Libraries/LibGUI/InputBox.cpp b/Userland/Libraries/LibGUI/InputBox.cpp
index d107c1a908..aae71d07b6 100644
--- a/Userland/Libraries/LibGUI/InputBox.cpp
+++ b/Userland/Libraries/LibGUI/InputBox.cpp
@@ -49,20 +49,20 @@ void InputBox::on_done(ExecResult result)
 
 void InputBox::build(InputType input_type)
 {
-    auto& widget = set_main_widget<Widget>();
+    auto widget = set_main_widget<Widget>().release_value_but_fixme_should_propagate_errors();
 
-    int text_width = widget.font().width(m_prompt);
-    int title_width = widget.font().width(title()) + 24 /* icon, plus a little padding -- not perfect */;
+    int text_width = widget->font().width(m_prompt);
+    int title_width = widget->font().width(title()) + 24 /* icon, plus a little padding -- not perfect */;
     int max_width = max(text_width, title_width);
 
-    widget.set_layout<VerticalBoxLayout>();
-    widget.set_fill_with_background_color(true);
-    widget.set_preferred_height(SpecialDimension::Fit);
+    widget->set_layout<VerticalBoxLayout>();
+    widget->set_fill_with_background_color(true);
+    widget->set_preferred_height(SpecialDimension::Fit);
 
-    widget.layout()->set_margins(6);
-    widget.layout()->set_spacing(6);
+    widget->layout()->set_margins(6);
+    widget->layout()->set_spacing(6);
 
-    auto& label_editor_container = widget.add<Widget>();
+    auto& label_editor_container = widget->add<Widget>();
     label_editor_container.set_layout<HorizontalBoxLayout>();
     label_editor_container.set_preferred_height(SpecialDimension::Fit);
 
@@ -83,7 +83,7 @@ void InputBox::build(InputType input_type)
     if (!m_placeholder.is_null())
         m_text_editor->set_placeholder(m_placeholder);
 
-    auto& button_container_outer = widget.add<Widget>();
+    auto& button_container_outer = widget->add<Widget>();
     button_container_outer.set_preferred_height(SpecialDimension::Fit);
     button_container_outer.set_layout<VerticalBoxLayout>();
 
@@ -113,7 +113,7 @@ void InputBox::build(InputType input_type)
     };
     m_text_editor->set_focus(true);
 
-    set_rect(x(), y(), max_width + 140, widget.effective_preferred_size().height().as_int());
+    set_rect(x(), y(), max_width + 140, widget->effective_preferred_size().height().as_int());
 }
 
 }
diff --git a/Userland/Libraries/LibGUI/MessageBox.cpp b/Userland/Libraries/LibGUI/MessageBox.cpp
index 518af0a350..8f6ab7a3d9 100644
--- a/Userland/Libraries/LibGUI/MessageBox.cpp
+++ b/Userland/Libraries/LibGUI/MessageBox.cpp
@@ -110,21 +110,21 @@ bool MessageBox::should_include_no_button() const
 
 void MessageBox::build()
 {
-    auto& widget = set_main_widget<Widget>();
+    auto widget = set_main_widget<Widget>().release_value_but_fixme_should_propagate_errors();
 
-    int text_width = widget.font().width(m_text);
+    int text_width = widget->font().width(m_text);
     auto number_of_lines = m_text.split('\n').size();
-    int padded_text_height = widget.font().glyph_height() * 1.6;
+    int padded_text_height = widget->font().glyph_height() * 1.6;
     int total_text_height = number_of_lines * padded_text_height;
     int icon_width = 0;
 
-    widget.set_layout<VerticalBoxLayout>();
-    widget.set_fill_with_background_color(true);
+    widget->set_layout<VerticalBoxLayout>();
+    widget->set_fill_with_background_color(true);
 
-    widget.layout()->set_margins(8);
-    widget.layout()->set_spacing(6);
+    widget->layout()->set_margins(8);
+    widget->layout()->set_spacing(6);
 
-    auto& message_container = widget.add<Widget>();
+    auto& message_container = widget->add<Widget>();
     message_container.set_layout<HorizontalBoxLayout>();
     message_container.layout()->set_spacing(8);
 
@@ -143,7 +143,7 @@ void MessageBox::build()
     if (m_type != Type::None)
         label.set_text_alignment(Gfx::TextAlignment::CenterLeft);
 
-    auto& button_container = widget.add<Widget>();
+    auto& button_container = widget->add<Widget>();
     button_container.set_layout<HorizontalBoxLayout>();
     button_container.set_fixed_height(24);
     button_container.layout()->set_spacing(8);
diff --git a/Userland/Libraries/LibGUI/PasswordInputDialog.cpp b/Userland/Libraries/LibGUI/PasswordInputDialog.cpp
index 80e30910a1..7be9cc9d00 100644
--- a/Userland/Libraries/LibGUI/PasswordInputDialog.cpp
+++ b/Userland/Libraries/LibGUI/PasswordInputDialog.cpp
@@ -22,30 +22,30 @@ PasswordInputDialog::PasswordInputDialog(Window* parent_window, DeprecatedString
     resize(340, 122);
     set_title(move(title));
 
-    auto& widget = set_main_widget<Widget>();
+    auto widget = set_main_widget<Widget>().release_value_but_fixme_should_propagate_errors();
 
-    widget.load_from_gml(password_input_dialog_gml);
+    widget->load_from_gml(password_input_dialog_gml);
 
-    auto& key_icon_label = *widget.find_descendant_of_type_named<GUI::Label>("key_icon_label");
+    auto& key_icon_label = *widget->find_descendant_of_type_named<GUI::Label>("key_icon_label");
 
     key_icon_label.set_icon(Gfx::Bitmap::try_load_from_file("/res/icons/32x32/key.png"sv).release_value_but_fixme_should_propagate_errors());
 
-    auto& server_label = *widget.find_descendant_of_type_named<GUI::Label>("server_label");
+    auto& server_label = *widget->find_descendant_of_type_named<GUI::Label>("server_label");
     server_label.set_text(move(server));
 
-    auto& username_label = *widget.find_descendant_of_type_named<GUI::Label>("username_label");
+    auto& username_label = *widget->find_descendant_of_type_named<GUI::Label>("username_label");
     username_label.set_text(move(username));
 
-    auto& password_box = *widget.find_descendant_of_type_named<GUI::PasswordBox>("password_box");
+    auto& password_box = *widget->find_descendant_of_type_named<GUI::PasswordBox>("password_box");
 
-    auto& ok_button = *widget.find_descendant_of_type_named<GUI::Button>("ok_button");
+    auto& ok_button = *widget->find_descendant_of_type_named<GUI::Button>("ok_button");
     ok_button.on_click = [&](auto) {
         dbgln("GUI::PasswordInputDialog: OK button clicked");
         m_password = password_box.text();
         done(ExecResult::OK);
     };
 
-    auto& cancel_button = *widget.find_descendant_of_type_named<GUI::Button>("cancel_button");
+    auto& cancel_button = *widget->find_descendant_of_type_named<GUI::Button>("cancel_button");
     cancel_button.on_click = [this](auto) {
         dbgln("GUI::PasswordInputDialog: Cancel button clicked");
         done(ExecResult::Cancel);
diff --git a/Userland/Libraries/LibGUI/ProcessChooser.cpp b/Userland/Libraries/LibGUI/ProcessChooser.cpp
index 246f507eca..82922fb9d9 100644
--- a/Userland/Libraries/LibGUI/ProcessChooser.cpp
+++ b/Userland/Libraries/LibGUI/ProcessChooser.cpp
@@ -31,11 +31,11 @@ ProcessChooser::ProcessChooser(StringView window_title, StringView button_label,
     resize(300, 340);
     center_on_screen();
 
-    auto& widget = set_main_widget<GUI::Widget>();
-    widget.set_fill_with_background_color(true);
-    widget.set_layout<GUI::VerticalBoxLayout>();
+    auto widget = set_main_widget<GUI::Widget>().release_value_but_fixme_should_propagate_errors();
+    widget->set_fill_with_background_color(true);
+    widget->set_layout<GUI::VerticalBoxLayout>();
 
-    m_table_view = widget.add<GUI::TableView>();
+    m_table_view = widget->add<GUI::TableView>();
     auto process_model = RunningProcessesModel::create();
     auto sorting_model = MUST(GUI::SortingProxyModel::create(process_model));
     sorting_model->set_sort_role(GUI::ModelRole::Display);
@@ -46,7 +46,7 @@ ProcessChooser::ProcessChooser(StringView window_title, StringView button_label,
 
     m_table_view->on_activation = [this](ModelIndex const& index) { set_pid_from_index_and_close(index); };
 
-    auto& button_container = widget.add<GUI::Widget>();
+    auto& button_container = widget->add<GUI::Widget>();
     button_container.set_fixed_height(30);
     button_container.set_layout<GUI::HorizontalBoxLayout>();
     button_container.layout()->set_margins({ 0, 4, 0 });
diff --git a/Userland/Libraries/LibGUI/SettingsWindow.cpp b/Userland/Libraries/LibGUI/SettingsWindow.cpp
index 007312fc32..55d827f24c 100644
--- a/Userland/Libraries/LibGUI/SettingsWindow.cpp
+++ b/Userland/Libraries/LibGUI/SettingsWindow.cpp
@@ -32,7 +32,7 @@ ErrorOr<NonnullRefPtr<SettingsWindow>> SettingsWindow::create(DeprecatedString t
     window->set_resizable(false);
     window->set_minimizable(false);
 
-    auto main_widget = TRY(window->try_set_main_widget<GUI::Widget>());
+    auto main_widget = TRY(window->set_main_widget<GUI::Widget>());
     main_widget->set_fill_with_background_color(true);
     (void)TRY(main_widget->try_set_layout<GUI::VerticalBoxLayout>());
     main_widget->layout()->set_margins(4);
diff --git a/Userland/Libraries/LibGUI/Window.h b/Userland/Libraries/LibGUI/Window.h
index 03a4bece7c..43652891b8 100644
--- a/Userland/Libraries/LibGUI/Window.h
+++ b/Userland/Libraries/LibGUI/Window.h
@@ -143,21 +143,13 @@ public:
     void set_main_widget(Widget*);
 
     template<class T, class... Args>
-    inline ErrorOr<NonnullRefPtr<T>> try_set_main_widget(Args&&... args)
+    inline ErrorOr<NonnullRefPtr<T>> set_main_widget(Args&&... args)
     {
         auto widget = TRY(T::try_create(forward<Args>(args)...));
         set_main_widget(widget.ptr());
         return widget;
     }
 
-    template<class T, class... Args>
-    inline T& set_main_widget(Args&&... args)
-    {
-        auto widget = T::construct(forward<Args>(args)...);
-        set_main_widget(widget.ptr());
-        return *widget;
-    }
-
     Widget* default_return_key_widget() { return m_default_return_key_widget; }
     Widget const* default_return_key_widget() const { return m_default_return_key_widget; }
     void set_default_return_key_widget(Widget*);
diff --git a/Userland/Libraries/LibGUI/Wizards/WizardDialog.cpp b/Userland/Libraries/LibGUI/Wizards/WizardDialog.cpp
index f41cd9e2ca..4654af9f4d 100644
--- a/Userland/Libraries/LibGUI/Wizards/WizardDialog.cpp
+++ b/Userland/Libraries/LibGUI/Wizards/WizardDialog.cpp
@@ -27,19 +27,19 @@ WizardDialog::WizardDialog(Window* parent_window)
     if (parent_window)
         set_icon(parent_window->icon());
 
-    auto& main_widget = set_main_widget<Widget>();
-    main_widget.set_fill_with_background_color(true);
-    main_widget.set_layout<VerticalBoxLayout>();
-    main_widget.layout()->set_spacing(0);
+    auto main_widget = set_main_widget<Widget>().release_value_but_fixme_should_propagate_errors();
+    main_widget->set_fill_with_background_color(true);
+    main_widget->set_layout<VerticalBoxLayout>();
+    main_widget->layout()->set_spacing(0);
 
-    m_page_container_widget = main_widget.add<Widget>();
+    m_page_container_widget = main_widget->add<Widget>();
     m_page_container_widget->set_fixed_size(500, 315);
     m_page_container_widget->set_layout<VerticalBoxLayout>();
 
-    auto& separator = main_widget.add<SeparatorWidget>(Gfx::Orientation::Horizontal);
+    auto& separator = main_widget->add<SeparatorWidget>(Gfx::Orientation::Horizontal);
     separator.set_fixed_height(2);
 
-    auto& nav_container_widget = main_widget.add<Widget>();
+    auto& nav_container_widget = main_widget->add<Widget>();
     nav_container_widget.set_layout<HorizontalBoxLayout>();
     nav_container_widget.set_fixed_height(42);
     nav_container_widget.layout()->set_margins({ 0, 10 });