MultiSelect: (breaking) renamed ImGuiMultiSelectFlags_ClearOnClickWindowVoid -> ImGuiMultiSelectFlags_ClearOnClickVoid. Added ImGuiMultiSelectFlags_ScopeWindow, ImGuiMultiSelectFlags_ScopeRect.

imgui.h

@@ -2734,10 +2734,11 @@ enum ImGuiMultiSelectFlags_
     ImGuiMultiSelectFlags_SingleSelect          = 1 << 0,   // Disable selecting more than one item. This is available to allow single-selection code to use same code/logic is desired, but may not be very useful.
     ImGuiMultiSelectFlags_NoSelectAll           = 1 << 1,   // Disable CTRL+A shortcut to set RequestSelectAll
     ImGuiMultiSelectFlags_ClearOnEscape         = 1 << 2,   // Clear selection when pressing Escape while scope is focused.
-    ImGuiMultiSelectFlags_ClearOnClickWindowVoid= 1 << 3,   // Clear selection when clicking on empty location within host window (use if BeginMultiSelect() covers a whole window)
+    ImGuiMultiSelectFlags_ClearOnClickVoid      = 1 << 3,   // Clear selection when clicking on empty location within scope.
-    //ImGuiMultiSelectFlags_ClearOnClickRectVoid= 1 << 4,   // Clear selection when clicking on empty location within rectangle covered by selection scope (use if multiple BeginMultiSelect() are used in the same host window)
+    ImGuiMultiSelectFlags_ScopeWindow           = 1 << 4,   // Scope for _ClearOnClickVoid and _BoxSelect is whole window (Default). Use if (use if BeginMultiSelect() covers a whole window.
-    ImGuiMultiSelectFlags_SelectOnClick         = 1 << 5,   // Apply selection on mouse down when clicking on unselected item. (Default)
+    ImGuiMultiSelectFlags_ScopeRect             = 1 << 5,   // Scope for _ClearOnClickVoid and _BoxSelect is rectangle covering submitted items. Use if multiple BeginMultiSelect() are used in the same host window.
-    ImGuiMultiSelectFlags_SelectOnClickRelease  = 1 << 6,   // Apply selection on mouse release when clicking an unselected item. Allow dragging an unselected item without altering selection.
+    ImGuiMultiSelectFlags_SelectOnClick         = 1 << 7,   // Apply selection on mouse down when clicking on unselected item. (Default)
+    ImGuiMultiSelectFlags_SelectOnClickRelease  = 1 << 8,   // Apply selection on mouse release when clicking an unselected item. Allow dragging an unselected item without altering selection.
 };
 
 // Multi-selection system

imgui_demo.cpp

@@ -3289,17 +3289,25 @@ static void ShowDemoWindowMultiSelect()
             static ExampleSelection selections_data[SCOPES_COUNT];
             ExampleSelectionAdapter selection_adapter; // Use default: Pass index to SetNextItemSelectionUserData(), store index in Selection
 
+            // Use ImGuiMultiSelectFlags_ScopeRect to not affect other selections in same window.
+            static ImGuiMultiSelectFlags flags = ImGuiMultiSelectFlags_ScopeRect | ImGuiMultiSelectFlags_ClearOnEscape;// | ImGuiMultiSelectFlags_ClearOnClickVoid;
+            if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ScopeWindow", &flags, ImGuiMultiSelectFlags_ScopeWindow) && (flags & ImGuiMultiSelectFlags_ScopeWindow))
+                flags &= ~ImGuiMultiSelectFlags_ScopeRect;
+            if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ScopeRect", &flags, ImGuiMultiSelectFlags_ScopeRect) && (flags & ImGuiMultiSelectFlags_ScopeRect))
+                flags &= ~ImGuiMultiSelectFlags_ScopeWindow;
+            ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnClickVoid", &flags, ImGuiMultiSelectFlags_ClearOnClickVoid);
+
             for (int selection_scope_n = 0; selection_scope_n < SCOPES_COUNT; selection_scope_n++)
             {
                 ExampleSelection* selection = &selections_data[selection_scope_n];
+
+                ImGuiMultiSelectIO* ms_io = ImGui::BeginMultiSelect(flags);
+                selection->ApplyRequests(ms_io, &selection_adapter, ITEMS_COUNT);
+
                 ImGui::SeparatorText("Selection scope");
                 ImGui::Text("Selection size: %d/%d", selection->GetSize(), ITEMS_COUNT);
                 ImGui::PushID(selection_scope_n);
 
-                ImGuiMultiSelectFlags flags = ImGuiMultiSelectFlags_ClearOnEscape; // | ImGuiMultiSelectFlags_ClearOnClickRectVoid
-                ImGuiMultiSelectIO* ms_io = ImGui::BeginMultiSelect(flags);
-                selection->ApplyRequests(ms_io, &selection_adapter, ITEMS_COUNT);
-
                 for (int n = 0; n < ITEMS_COUNT; n++)
                 {
                     char label[64];
@@ -3354,8 +3362,16 @@ static void ShowDemoWindowMultiSelect()
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_SingleSelect", &flags, ImGuiMultiSelectFlags_SingleSelect);
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoSelectAll", &flags, ImGuiMultiSelectFlags_NoSelectAll);
             ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnEscape", &flags, ImGuiMultiSelectFlags_ClearOnEscape);
-            ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnClickWindowVoid", &flags, ImGuiMultiSelectFlags_ClearOnClickWindowVoid);
+            ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnClickVoid", &flags, ImGuiMultiSelectFlags_ClearOnClickVoid);
-            ImGui::CheckboxFlags("ImGuiMultiSelectFlags_SelectOnClickRelease", &flags, ImGuiMultiSelectFlags_SelectOnClickRelease); ImGui::SameLine();  HelpMarker("Allow dragging an unselected item without altering selection.");
+            if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ScopeWindow", &flags, ImGuiMultiSelectFlags_ScopeWindow) && (flags & ImGuiMultiSelectFlags_ScopeWindow))
+                flags &= ~ImGuiMultiSelectFlags_ScopeRect;
+            if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ScopeRect", &flags, ImGuiMultiSelectFlags_ScopeRect) && (flags & ImGuiMultiSelectFlags_ScopeRect))
+                flags &= ~ImGuiMultiSelectFlags_ScopeWindow;
+            if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_SelectOnClick", &flags, ImGuiMultiSelectFlags_SelectOnClick) && (flags & ImGuiMultiSelectFlags_SelectOnClick))
+                flags &= ~ImGuiMultiSelectFlags_SelectOnClickRelease;
+            if (ImGui::CheckboxFlags("ImGuiMultiSelectFlags_SelectOnClickRelease", &flags, ImGuiMultiSelectFlags_SelectOnClickRelease) && (flags & ImGuiMultiSelectFlags_SelectOnClickRelease))
+                flags &= ~ImGuiMultiSelectFlags_SelectOnClick;
+            ImGui::SameLine();  HelpMarker("Allow dragging an unselected item without altering selection.");
 
             // Initialize default list with 1000 items.
             static ImVector<int> items;
@@ -9826,7 +9842,7 @@ struct ExampleAssetsBrowser
             ImGui::SetCursorScreenPos(start_pos);
 
             // Multi-select
-            ImGuiMultiSelectFlags ms_flags = ImGuiMultiSelectFlags_ClearOnEscape | ImGuiMultiSelectFlags_ClearOnClickWindowVoid;
+            ImGuiMultiSelectFlags ms_flags = ImGuiMultiSelectFlags_ClearOnEscape | ImGuiMultiSelectFlags_ClearOnClickVoid;
             if (AllowDragUnselected)
                 ms_flags |= ImGuiMultiSelectFlags_SelectOnClickRelease; // To allow dragging an unselected item without altering selection.
 

imgui_internal.h

@@ -1720,6 +1720,8 @@ struct IMGUI_API ImGuiMultiSelectTempData
     ImGuiMultiSelectState*  Storage;
     ImGuiID                 FocusScopeId;       // Copied from g.CurrentFocusScopeId (unless another selection scope was pushed manually)
     ImGuiMultiSelectFlags   Flags;
+    ImVec2                  ScopeRectMin;
+    ImVec2                  BackupCursorMaxPos;
     ImGuiKeyChord           KeyMods;
     bool                    LoopRequestClear;
     bool                    LoopRequestSelectAll;
@@ -1729,7 +1731,6 @@ struct IMGUI_API ImGuiMultiSelectTempData
     bool                    NavIdPassedBy;
     bool                    RangeSrcPassedBy;   // Set by the item that matches RangeSrcItem.
     bool                    RangeDstPassedBy;   // Set by the item that matches NavJustMovedToId when IsSetRange is set.
-    //ImRect                Rect;               // Extent of selection scope between BeginMultiSelect() / EndMultiSelect(), used by ImGuiMultiSelectFlags_ClearOnClickRectVoid.
 
     ImGuiMultiSelectTempData()  { Clear(); }
     void Clear()            { size_t io_sz = sizeof(IO); IO.Clear(); memset((void*)(&IO + 1), 0, sizeof(*this) - io_sz); } // Zero-clear except IO

imgui_widgets.cpp

@@ -7138,6 +7138,8 @@ ImGuiMultiSelectIO* ImGui::BeginMultiSelect(ImGuiMultiSelectFlags flags)
     ms->FocusScopeId = id;
     ms->Flags = flags;
     ms->IsFocused = (ms->FocusScopeId == g.NavFocusScopeId);
+    ms->BackupCursorMaxPos = window->DC.CursorMaxPos;
+    ms->ScopeRectMin = window->DC.CursorMaxPos = window->DC.CursorPos;
     PushFocusScope(ms->FocusScopeId);
 
     // Use copy of keyboard mods at the time of the request, otherwise we would requires mods to be held for an extra frame.
@@ -7208,6 +7210,7 @@ ImGuiMultiSelectIO* ImGui::EndMultiSelect()
     ImGuiContext& g = *GImGui;
     ImGuiMultiSelectTempData* ms = g.CurrentMultiSelect;
     ImGuiMultiSelectState* storage = ms->Storage;
+    ImGuiWindow* window = g.CurrentWindow;
     IM_ASSERT(ms->FocusScopeId == g.CurrentFocusScopeId);
     IM_ASSERT(g.CurrentMultiSelect != NULL && storage->Window == g.CurrentWindow);
 
@@ -7230,17 +7233,23 @@ ImGuiMultiSelectIO* ImGui::EndMultiSelect()
     if (ms->IsEndIO == false)
         ms->IO.Requests.resize(0);
 
+    const ImRect scope_rect(ms->ScopeRectMin, ImMax(window->DC.CursorMaxPos, ms->ScopeRectMin));
+    const bool scope_hovered = (ms->Flags & ImGuiMultiSelectFlags_ScopeRect) ? IsMouseHoveringRect(scope_rect.Min, scope_rect.Max) : IsWindowHovered();
+
     // Clear selection when clicking void?
     // We specifically test for IsMouseDragPastThreshold(0) == false to allow box-selection!
-    if (ms->Flags & ImGuiMultiSelectFlags_ClearOnClickWindowVoid)
+    if (scope_hovered && g.HoveredId == 0)
-        if (IsWindowHovered() && g.HoveredId == 0)
+    {
+        if (ms->Flags & ImGuiMultiSelectFlags_ClearOnClickVoid)
             if (IsMouseReleased(0) && IsMouseDragPastThreshold(0) == false && g.IO.KeyMods == ImGuiMod_None)
             {
                 ms->IO.Requests.resize(0);
                 ms->IO.Requests.push_back(ImGuiSelectionRequest(ImGuiSelectionRequestType_Clear));
             }
+    }
 
     // Unwind
+    window->DC.CursorMaxPos = ImMax(ms->BackupCursorMaxPos, window->DC.CursorMaxPos);
     ms->FocusScopeId = 0;
     ms->Flags = ImGuiMultiSelectFlags_None;
     PopFocusScope();