Multi-Select: reworked ImGuiMultiSelectFlags_NoAutoSelect as it carried side-effects that were hardcoded/designed to use multi-selection on checkboxes. (#9391)

docs/CHANGELOG.txt

@@ -77,6 +77,14 @@ Other Changes:
   - Headers: fixed label being clipped early to reserve space for a sort marker
     even when no sort marker is displayed. Auto-fitting a column still accounts
     for the possible marker, so that sorting after an auto-fit doesn't clip the label.
+- Multi-Select
+  - Reworked ImGuiMultiSelectFlags_NoAutoSelect as it carried side-effects that
+    were hardcoded/designed to use multi-selection on checkboxes. (#9391)
+    Specifically removed those undocumented behaviors from _NoAutoSelect:
+    - Clicking a selected/checked item always unselect/uncheck.
+    - Shift+Click inverts targets value and copy to range.
+    - Shift+Keyboard copy selection source value to range.
+    Those behaviors are still happening on checkboxes used within multi-selection.
 - Fonts:
   - Added `IMGUI_DISABLE_DEFAULT_FONT_BITMAP`/`IMGUI_DISABLE_DEFAULT_FONT_VECTOR` to
     disable embedding either fonts separately. (#9407)

imgui.h

@@ -3056,6 +3056,7 @@ enum ImGuiMultiSelectFlags_
     ImGuiMultiSelectFlags_NavWrapX              = 1 << 16,  // [Temporary] Enable navigation wrapping on X axis. Provided as a convenience because we don't have a design for the general Nav API for this yet. When the more general feature be public we may obsolete this flag in favor of new one.
     ImGuiMultiSelectFlags_NoSelectOnRightClick  = 1 << 17,  // Disable default right-click processing, which selects item on mouse down, and is designed for context-menus.
     ImGuiMultiSelectFlags_SelectOnMask_         = ImGuiMultiSelectFlags_SelectOnAuto | ImGuiMultiSelectFlags_SelectOnClickAlways | ImGuiMultiSelectFlags_SelectOnClickRelease,
+    ImGuiMultiSelectFlags_CheckboxMode_         = 1 << 20,  // [Internal]
 
     // Obsolete names
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS

imgui_internal.h

@@ -3637,7 +3637,7 @@ namespace ImGui
 
     // Multi-Select API
     IMGUI_API void          MultiSelectItemHeader(ImGuiID id, bool* p_selected, ImGuiButtonFlags* p_button_flags);
-    IMGUI_API void          MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed);
+    IMGUI_API void          MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed, ImGuiMultiSelectFlags extra_flags = 0);
     IMGUI_API void          MultiSelectAddSetAll(ImGuiMultiSelectTempData* ms, bool selected);
     IMGUI_API void          MultiSelectAddSetRange(ImGuiMultiSelectTempData* ms, bool selected, int range_dir, ImGuiSelectionUserData first_item, ImGuiSelectionUserData last_item);
     inline ImGuiBoxSelectState*     GetBoxSelectState(ImGuiID id)   { ImGuiContext& g = *GImGui; return (id != 0 && g.BoxSelectState.ID == id && g.BoxSelectState.IsActive) ? &g.BoxSelectState : NULL; }

imgui_widgets.cpp

@@ -1274,7 +1274,7 @@ bool ImGui::Checkbox(const char* label, bool* v)
 
     // Range-Selection/Multi-selection support (footer)
     if (is_multi_select)
-        MultiSelectItemFooter(id, &checked, &pressed);
+        MultiSelectItemFooter(id, &checked, &pressed, ImGuiMultiSelectFlags_CheckboxMode_);
     else if (pressed)
         checked = !checked;
 
@@ -8307,7 +8307,7 @@ void ImGui::MultiSelectItemHeader(ImGuiID id, bool* p_selected, ImGuiButtonFlags
 // - Altering selection based on Ctrl/Shift modifiers, both for keyboard and mouse.
 // - Record current selection state for RangeSrc
 // This is all rather complex, best to run and refer to "widgets_multiselect_xxx" tests in imgui_test_suite.
-void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed)
+void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed, ImGuiMultiSelectFlags extra_flags)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
@@ -8327,7 +8327,7 @@ void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed)
 
     ImGuiSelectionUserData item_data = g.NextItemData.SelectionUserData;
 
-    ImGuiMultiSelectFlags flags = ms->Flags;
+    ImGuiMultiSelectFlags flags = ms->Flags | extra_flags;
     const bool is_singleselect = (flags & ImGuiMultiSelectFlags_SingleSelect) != 0;
     bool is_ctrl = (ms->KeyMods & ImGuiMod_Ctrl) != 0;
     bool is_shift = (ms->KeyMods & ImGuiMod_Shift) != 0;
@@ -8481,7 +8481,7 @@ void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed)
             //IM_ASSERT(storage->HasRangeSrc && storage->HasRangeValue);
             if (storage->RangeSrcItem == ImGuiSelectionUserData_Invalid)
                 storage->RangeSrcItem = item_data;
-            if ((flags & ImGuiMultiSelectFlags_NoAutoSelect) == 0)
+            if ((flags & ImGuiMultiSelectFlags_CheckboxMode_) == 0)
             {
                 // Shift+Arrow always select
                 // Ctrl+Shift+Arrow copy source selection state (already stored by BeginMultiSelect() in storage->RangeSelected)
@@ -8501,7 +8501,7 @@ void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed)
         else
         {
             // Ctrl inverts selection, otherwise always select
-            if ((flags & ImGuiMultiSelectFlags_NoAutoSelect) == 0)
+            if ((flags & ImGuiMultiSelectFlags_CheckboxMode_) == 0)
                 selected = is_ctrl ? !selected : true;
             else
                 selected = !selected;