ImDrawList: Fixed CloneOutput() helper crashing. Also removed unnecessary risk from ImDrawList::Clear(), draw lists are being clear before use each frame anyway. (#1860)

docs/CHANGELOG.txt

@@ -42,7 +42,8 @@ Breaking Changes:
   the new names and equivalent.
 
 Other Changes:
-- ImDrawList::ChannelsSplit(), ImDrawListSlitter: Fixed an issue with merging draw commands between channel 0 and 1. (#2624)
+- ImDrawList: Fixed CloneOutput() helper crashing. (#1860) [@gviot]
+- ImDrawListSlitter, ImDrawList::ChannelsSplit(), : Fixed an issue with merging draw commands between channel 0 and 1. (#2624)
 
 
 -----------------------------------------------------------------------

imgui_draw.cpp

@@ -365,7 +365,7 @@ void ImDrawList::Clear()
     CmdBuffer.resize(0);
     IdxBuffer.resize(0);
     VtxBuffer.resize(0);
-    Flags = _Data->InitialFlags;
+    Flags = _Data ? _Data->InitialFlags : ImDrawListFlags_None;
     _VtxCurrentOffset = 0;
     _VtxCurrentIdx = 0;
     _VtxWritePtr = NULL;
@@ -392,7 +392,7 @@ void ImDrawList::ClearFreeMemory()
 
 ImDrawList* ImDrawList::CloneOutput() const
 {
-    ImDrawList* dst = IM_NEW(ImDrawList(NULL));
+    ImDrawList* dst = IM_NEW(ImDrawList(_Data));
     dst->CmdBuffer = CmdBuffer;
     dst->IdxBuffer = IdxBuffer;
     dst->VtxBuffer = VtxBuffer;