ImDrawListSplitter: fixed an issue merging channels if the last submi…

…tted draw command used a different texture. (#2506)

docs/CHANGELOG.txt

@@ -56,6 +56,7 @@ Other Changes:
   Otherwise we render ellipsis using '.' from the font from where we trim excessive spacing to make it as narrow
   as possible. (#2775) [@rokups]
 - ImDrawList: clarified the name of many parameters so reading the code is a little easier. (#2740)
+- ImDrawListSplitter: fixed an issue merging channels if the last submitted draw command used a different texture. (#2506)
 - Using offsetof() when available in C++11. Avoids Clang sanitizer complaining about old-style macros. (#94)
 - Added a mechanism to compact/free the larger allocations of unused windows (buffers are compacted when
   a window is unused for 60 seconds, as per io.ConfigWindowsMemoryCompactTimer = 60.0f). Note that memory

imgui_draw.cpp

@@ -1301,6 +1301,7 @@ 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;
 }