Drag Feature / "Insert Here" in model tree not working

[akelly]

TL/DR: exiting CP and re-opening it fixed the issue.  But no idea why it happened in the first place.

Using CP4 in part mode. Earlier today, for some reason, I couldn't drag features in the model tree to re-order them or the Insert Here to activate Insert Mode.  I could select them, and RMB worked.  And Reorder and Insert Mode worked through the Operations menu.  Pretty darn inconvenient.  And frustrating for a while.  Ultimately I exited CP and re-launched.  Then it was working again.

Any idea what could have happened to break dragging in the model tree?

[Chris3]

I have had this problem myself. I could never figure out the exact steps to reproduce so I wasn't able to file a ticket with PTC but this often proceeded a crash of the program so I learned to save and restart anytime I experienced it.