Fixes for MSVC static analyzers (wider range of versions). (#3938, #4073) + warning fix (#4089) + comments.

imgui.cpp

@@ -4069,7 +4069,7 @@ void ImGui::NewFrame()
     g.CurrentWindowStack.resize(0);
     g.BeginPopupStack.resize(0);
     g.ItemFlagsStack.resize(0);
-    g.ItemFlagsStack.push_back(ImGuiItemFlags_Default_);
+    g.ItemFlagsStack.push_back(ImGuiItemFlags_None);
     g.GroupStack.resize(0);
     ClosePopupsOverWindow(g.NavWindow, false);
 
@@ -4554,6 +4554,7 @@ static void FindHoveredWindow()
     for (int i = g.Windows.Size - 1; i >= 0; i--)
     {
         ImGuiWindow* window = g.Windows[i];
+        IM_MSVC_WARNING_SUPPRESS(28182); // [Static Analyzer] Dereferencing NULL pointer.
         if (!window->Active || window->Hidden)
             continue;
         if (window->Flags & ImGuiWindowFlags_NoMouseInputs)
@@ -9509,6 +9510,7 @@ static void ImGui::NavEndFrame()
 static int ImGui::FindWindowFocusIndex(ImGuiWindow* window)
 {
     ImGuiContext& g = *GImGui;
+    IM_UNUSED(g);
     int order = window->FocusOrder;
     IM_ASSERT(g.WindowsFocusOrder[order] == window);
     return order;
@@ -9716,7 +9718,7 @@ void ImGui::NavUpdateWindowingOverlay()
     for (int n = g.WindowsFocusOrder.Size - 1; n >= 0; n--)
     {
         ImGuiWindow* window = g.WindowsFocusOrder[n];
-        IM_MSVC_WARNING_SUPPRESS(6011); // Static Analysis false positive "warning C6011: Dereferencing NULL pointer 'window'"
+        IM_ASSERT(window != NULL); // Fix static analyzers
         if (!IsWindowNavFocusable(window))
             continue;
         const char* label = window->Name;

imgui_internal.h

@@ -707,18 +707,17 @@ enum ImGuiItemFlags_
     ImGuiItemFlags_NoNavDefaultFocus        = 1 << 4,  // false
     ImGuiItemFlags_SelectableDontClosePopup = 1 << 5,  // false    // MenuItem/Selectable() automatically closes current Popup window
     ImGuiItemFlags_MixedValue               = 1 << 6,  // false    // [BETA] Represent a mixed/indeterminate value, generally multi-selection where values differ. Currently only supported by Checkbox() (later should support all sorts of widgets)
-    ImGuiItemFlags_ReadOnly                 = 1 << 7,  // false    // [ALPHA] Allow hovering interactions but underlying value is not changed.
-    ImGuiItemFlags_Default_                 = 0
+    ImGuiItemFlags_ReadOnly                 = 1 << 7   // false    // [ALPHA] Allow hovering interactions but underlying value is not changed.
 };
 
 // Storage for LastItem data
 enum ImGuiItemStatusFlags_
 {
     ImGuiItemStatusFlags_None               = 0,
-    ImGuiItemStatusFlags_HoveredRect        = 1 << 0,
-    ImGuiItemStatusFlags_HasDisplayRect     = 1 << 1,   // LastItemDisplayRect is valid
+    ImGuiItemStatusFlags_HoveredRect        = 1 << 0,   // Mouse position is within item rectangle (does NOT mean that the window is in correct z-order and can be hovered!, this is only one part of the most-common IsItemHovered test)
+    ImGuiItemStatusFlags_HasDisplayRect     = 1 << 1,   // window->DC.LastItemDisplayRect is valid
     ImGuiItemStatusFlags_Edited             = 1 << 2,   // Value exposed by item was edited in the current frame (should match the bool return value of most widgets)
-    ImGuiItemStatusFlags_ToggledSelection   = 1 << 3,   // Set when Selectable(), TreeNode() reports toggling a selection. We can't report "Selected" because reporting the change allows us to handle clipping with less issues.
+    ImGuiItemStatusFlags_ToggledSelection   = 1 << 3,   // Set when Selectable(), TreeNode() reports toggling a selection. We can't report "Selected", only state changes, in order to easily handle clipping with less issues.
     ImGuiItemStatusFlags_ToggledOpen        = 1 << 4,   // Set when TreeNode() reports toggling their open state.
     ImGuiItemStatusFlags_HasDeactivated     = 1 << 5,   // Set if the widget/group is able to provide data for the ImGuiItemStatusFlags_Deactivated flag.
     ImGuiItemStatusFlags_Deactivated        = 1 << 6,   // Only valid if ImGuiItemStatusFlags_HasDeactivated is set.