Replace non-leading tabs with spaces, using:

find -type f |  # list all regular files
  grep -E '\.(h|cpp|mm)$' |  # filter for source files
  grep -v '/mt_' |  # filter out generated files
  grep -v '/vendor/' | # and vendored GL
  xargs -n 1 -P $(nproc) ./replace_non_leading_tabs.lua  # reformat everything

include/IGUIElement.h

@@ -706,7 +706,7 @@ protected:
 	void addChildToEnd(IGUIElement *child)
 	{
 		if (child) {
-			child->grab();	 // prevent destruction when removed
+			child->grab();   // prevent destruction when removed
 			child->remove(); // remove from old parent
 			child->LastParentRect = getAbsolutePosition();
 			child->Parent = this;