Updated ImGui.

3rdparty/ocornut-imgui/imgui.cpp

@@ -490,9 +490,11 @@
  - input text: flag to disable live update of the user buffer (also applies to float/int text input) 
  - input text: resize behavior - field could stretch when being edited? hover tooltip shows more text?
  - input text: add ImGuiInputTextFlags_EnterToApply? (off #218)
+ - input text: add discard flag (e.g. ImGuiInputTextFlags_DiscardActiveBuffer) or make it easier to clear active focus for text replacement during edition (#725)
  - input text multi-line: don't directly call AddText() which does an unnecessary vertex reserve for character count prior to clipping. and/or more line-based clipping to AddText(). and/or reorganize TextUnformatted/RenderText for more efficiency for large text (e.g TextUnformatted could clip and log separately, etc).
  - input text multi-line: way to dynamically grow the buffer without forcing the user to initially allocate for worse case (follow up on #200)
  - input text multi-line: line numbers? status bar? (follow up on #200)
+ - input text multi-line: behave better when user changes input buffer while editing is active (even though it is illegal behavior). namely, the change of buffer can create a scrollbar glitch (#725)
  - input text: allow centering/positioning text so that ctrl+clicking Drag or Slider keeps the textual value at the same pixel position.
  - input number: optional range min/max for Input*() functions
  - input number: holding [-]/[+] buttons could increase the step speed non-linearly (or user-controlled)
@@ -8117,6 +8119,8 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
         Dummy(text_size + ImVec2(0.0f, g.FontSize)); // Always add room to scroll an extra line
         EndChildFrame();
         EndGroup();
+        if (g.ActiveId == id || is_currently_scrolling) // Set LastItemId which was lost by EndChild/EndGroup, so user can use IsItemActive()
+            window->DC.LastItemId = g.ActiveId;
     }
 
     if (is_password)