wwmayer

This is the line where the placement is reset: https://github.com/FreeCAD/FreeCAD/blob/ed77603af999525b65dcfc4a41337f15a052c9ef/src/Gui/Tree.cpp#L2154C25-L2154C80 What happens there is that the identity matrix is set and not the original matrix. The reason for this is...

> I only moved this code when refactoring the dropEvent function. See the file before my PR I know it's there for almost 5 years. Until now it never caused...

With the old drag and drop implementation it was explicitly checked that if a top-level item is moved to its parent document item then it was filtered out. ``` auto...

> This is almost instantaneous on a single simple object, but it becomes too slow on many occasions : This depends on the complexity of an object. It can even...

The behaviour depends on user settings: https://github.com/FreeCAD/FreeCAD/blob/e4eb8598495fa6e3d470ea700eb928c42aaefafe/src/Mod/Help/Help.py#L112 By default the system browser isn't used.

> what happens when opening old files that have these objects? A message will be printed that the object couldn't be restored. > do you know how we can migrate...

> Could we also keep the old object around and migrate it in the onDocumentRestored method similar to how it's documented here: https://wiki.freecad.org/Scripted_objects_migration ? No, this will cause serious problems:...

I guess it's used rather rarely. But nevertheless with this trick the object can be restored. Add the following code snippets to Mod/Measure/MeasureDistance.h/cpp: ``` class MeasureDistanceType: public Base::BaseClass { public:...

> For some reason the newly created measurements are not visible tho. I have observed this too but couldn't spot the code block where the view provider fails to show...

> and between two arbitrary points on the geometry. You can measure the distance between two arbitrary vertexes but not between two arbitrary points. The advantage is that the measurement...