Catalog->Catalog Management... creates a dialog window in the "background", I am not able to access it. I can Alt+TAB to it but it is not brought forward when I release the keys.
Edited to add: Hovering mouse over the PM+ icon on the taskbar sows a mini dialog. I can close it by clicking the "X" and bring it back via Catalog->Catalog Management... A PM+ restart nor PC restart changes anything.