MultiSelect: added ImGuiMultiSelectFlags_NoSelectOnRightClick. (#8200, #9015)

Author: ocornut

docs/CHANGELOG.txt

@@ -53,6 +53,9 @@ Other Changes:
   resizing the parent window while keeping the multi-line field active (which is
   most typically achieved when resizing programmatically or via a docking layout
   reacting to a platform window resize). (#3237, #9007) [@anton-kl, @ocornut]
+- MultiSelect: added ImGuiMultiSelectFlags_NoSelectOnRightClick to disable default
+  right-click processing, which selects item on mouse down and is designed for
+  context-menus. (#8200, #9015)
 - Backends: Vulkan: added IMGUI_IMPL_VULKAN_VOLK_FILENAME to configure path to
   Volk (default to "volk.h"). (#9008, #7722, #6582, #4854) [@mwlasiuk]
 - Backends: WebGPU: update to compile with Dawn and Emscripten's 4.0.10+

imgui.h

@@ -3003,6 +3003,7 @@ enum ImGuiMultiSelectFlags_
     ImGuiMultiSelectFlags_SelectOnClickRelease  = 1 << 14,  // Apply selection on mouse release when clicking an unselected item. Allow dragging an unselected item without altering selection.
     //ImGuiMultiSelectFlags_RangeSelect2d       = 1 << 15,  // Shift+Selection uses 2d geometry instead of linear sequence, so possible to use Shift+up/down to select vertically in grid. Analogous to what BoxSelect does.
     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.
 };
 
 // Main IO structure returned by BeginMultiSelect()/EndMultiSelect().

imgui_demo.cpp

@@ -2647,6 +2647,10 @@ static void DemoWindowWidgetsSelectionAndMultiSelect(ImGuiDemoWindowData* demo_d
     {
         HelpMarker("Selections can be built using Selectable(), TreeNode() or other widgets. Selection state is owned by application code/data.");
 
+        ImGui::BulletText("Wiki page:");
+        ImGui::SameLine();
+        ImGui::TextLinkOpenURL("imgui/wiki/Multi-Select", "https://github.com/ocornut/imgui/wiki/Multi-Select");
+
         // Without any fancy API: manage single-selection yourself.
         IMGUI_DEMO_MARKER("Widgets/Selection State/Single-Select");
         if (ImGui::TreeNode("Single-Select"))
@@ -3180,6 +3184,7 @@ static void DemoWindowWidgetsSelectionAndMultiSelect(ImGuiDemoWindowData* demo_d
                 ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoAutoSelect", &flags, ImGuiMultiSelectFlags_NoAutoSelect);
                 ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoAutoClear", &flags, ImGuiMultiSelectFlags_NoAutoClear);
                 ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoAutoClearOnReselect", &flags, ImGuiMultiSelectFlags_NoAutoClearOnReselect);
+                ImGui::CheckboxFlags("ImGuiMultiSelectFlags_NoSelectOnRightClick", &flags, ImGuiMultiSelectFlags_NoSelectOnRightClick);
                 ImGui::CheckboxFlags("ImGuiMultiSelectFlags_BoxSelect1d", &flags, ImGuiMultiSelectFlags_BoxSelect1d);
                 ImGui::CheckboxFlags("ImGuiMultiSelectFlags_BoxSelect2d", &flags, ImGuiMultiSelectFlags_BoxSelect2d);
                 ImGui::CheckboxFlags("ImGuiMultiSelectFlags_BoxSelectNoScroll", &flags, ImGuiMultiSelectFlags_BoxSelectNoScroll);

imgui_widgets.cpp

@@ -8213,8 +8213,8 @@ void ImGui::MultiSelectItemFooter(ImGuiID id, bool* p_selected, bool* p_pressed)
         }
 
     // Right-click handling.
-    // FIXME-MULTISELECT: Currently filtered out by ImGuiMultiSelectFlags_NoAutoSelect but maybe should be moved to Selectable(). See https://github.com/ocornut/imgui/pull/5816
-    if (hovered && IsMouseClicked(1) && (flags & ImGuiMultiSelectFlags_NoAutoSelect) == 0)
+    // FIXME-MULTISELECT: Maybe should be moved to Selectable()? Also see #5816, #8200, #9015
+    if (hovered && IsMouseClicked(1) && (flags & (ImGuiMultiSelectFlags_NoAutoSelect | ImGuiMultiSelectFlags_NoSelectOnRightClick)) == 0)
     {
         if (g.ActiveId != 0 && g.ActiveId != id)
             ClearActiveID();