Merge branch 'master' into docking

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

imgui_draw.cpp

@@ -1307,6 +1307,7 @@ void ImDrawListSplitter::Merge(ImDrawList* draw_list)
     }
     draw_list->_IdxWritePtr = idx_write;
     draw_list->UpdateClipRect(); // We call this instead of AddDrawCmd(), so that empty channels won't produce an extra draw call.
+    draw_list->UpdateTextureID();
     _Count = 1;
 }