Fixes for tooltip over modals leading to incorrect modal dimming. (#4729)

Amend 23ef6c1. Should rework tooltip to be in a consistent position in g.Windows[]

imgui.cpp

@@ -4482,7 +4482,7 @@ ImGuiWindow* ImGui::FindBottomMostVisibleWindowWithinBeginStack(ImGuiWindow* par
             continue;
         if (!IsWindowWithinBeginStackOf(window, parent_window))
             break;
-        if (IsWindowActiveAndVisible(window))
+        if (IsWindowActiveAndVisible(window) && GetWindowDisplayLayer(window) <= GetWindowDisplayLayer(parent_window))
             bottom_most_visible_window = window;
     }
     return bottom_most_visible_window;

imgui.h

@@ -64,7 +64,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.86 WIP"
-#define IMGUI_VERSION_NUM           18517
+#define IMGUI_VERSION_NUM           18518
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE