Do not remove overriden property from original xml declaration
When an override property is set, the MergeProxyDefinition
replaces the overridden property with the new one and then removes it definitively from the original XML declaration.
So, when a new plugin is loaded, and the entire proxy map is rebuilt, there are no override properties left anymore (as they were deleted during the first pass).
This MR attempts to fix this by ignoring all elements with the override attribute when adding remaining elements, instead of removing the override property from the original XML declaration.
Fixes #21016 (closed)
Edited by Timothée Couble