From 65b46f62ef1a90ea0306346633cedc08e914547c Mon Sep 17 00:00:00 2001
From: omar <omarcornut@gmail.com>
Date: Tue, 31 Jul 2018 17:26:42 +0200
Subject: [PATCH] Fixed PushID() from keeping alive the new ID Stack top value
 (if a previously active widget shared the ID it would be erroneously kept
 alive) (drag and drop demo could soft-lock the UI until pressing Escape!)

---
 CHANGELOG.txt    |  1 +
 imgui.cpp        | 14 ++++++++++----
 imgui_internal.h |  1 +
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index aa89705e..af295e1a 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -59,6 +59,7 @@ Other Changes:
  - Misc: Added ImGuiMouseCursor_Hand cursor enum + corresponding software cursor. (#1913, 1914) [@aiekick, @ocornut] 
  - Misc: Tweaked software mouse cursor offset to match the offset of the corresponding Windows 10 cursors.
  - Made assertion more clear when trying to call Begin() outside of the NewFrame()..EndFrame() scope. (#1987)
+ - Fixed PushID() from keeping alive the new ID Stack top value (if a previously active widget shared the ID it would be erroneously kept alive).  
  - Fixed horizontal mouse wheel not forwarding the request to the parent window if ImGuiWindowFlags_NoScrollWithMouse is set. (#1463, #1380, #1502)
  - Fixed a include build issue for Cygwin in non-POSIX (Win32) mode. (#1917, #1319, #276)
  - OS/Windows: Fixed missing ImmReleaseContext() call in the default Win32 IME handler. (#1932) [@vby]
diff --git a/imgui.cpp b/imgui.cpp
index 546bb2a8..be188efe 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -2194,6 +2194,12 @@ ImGuiID ImGuiWindow::GetIDNoKeepAlive(const char* str, const char* str_end)
     return ImHash(str, str_end ? (int)(str_end - str) : 0, seed);
 }
 
+ImGuiID ImGuiWindow::GetIDNoKeepAlive(const void* ptr)
+{
+    ImGuiID seed = IDStack.back();
+    return ImHash(&ptr, sizeof(void*), seed);
+}
+
 // This is only used in rare/specific situations to manufacture an ID out of nowhere.
 ImGuiID ImGuiWindow::GetIDFromRectangle(const ImRect& r_abs)
 {
@@ -8929,26 +8935,26 @@ void ImGui::SetNextTreeNodeOpen(bool is_open, ImGuiCond cond)
 void ImGui::PushID(const char* str_id)
 {
     ImGuiWindow* window = GetCurrentWindowRead();
-    window->IDStack.push_back(window->GetID(str_id));
+    window->IDStack.push_back(window->GetIDNoKeepAlive(str_id));
 }
 
 void ImGui::PushID(const char* str_id_begin, const char* str_id_end)
 {
     ImGuiWindow* window = GetCurrentWindowRead();
-    window->IDStack.push_back(window->GetID(str_id_begin, str_id_end));
+    window->IDStack.push_back(window->GetIDNoKeepAlive(str_id_begin, str_id_end));
 }
 
 void ImGui::PushID(const void* ptr_id)
 {
     ImGuiWindow* window = GetCurrentWindowRead();
-    window->IDStack.push_back(window->GetID(ptr_id));
+    window->IDStack.push_back(window->GetIDNoKeepAlive(ptr_id));
 }
 
 void ImGui::PushID(int int_id)
 {
     const void* ptr_id = (void*)(intptr_t)int_id;
     ImGuiWindow* window = GetCurrentWindowRead();
-    window->IDStack.push_back(window->GetID(ptr_id));
+    window->IDStack.push_back(window->GetIDNoKeepAlive(ptr_id));
 }
 
 void ImGui::PopID()
diff --git a/imgui_internal.h b/imgui_internal.h
index cdabcd35..1d932a55 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -1045,6 +1045,7 @@ public:
     ImGuiID     GetID(const char* str, const char* str_end = NULL);
     ImGuiID     GetID(const void* ptr);
     ImGuiID     GetIDNoKeepAlive(const char* str, const char* str_end = NULL);
+    ImGuiID     GetIDNoKeepAlive(const void* ptr);
     ImGuiID     GetIDFromRectangle(const ImRect& r_abs);
 
     // We don't use g.FontSize because the window may be != g.CurrentWidow.