This bug has proven to be perfectly repeatable on my system. I'm using the LabVIEW Core 3 Course Project to reproduce:
1. Open the block diagram of a VI with while loop or case structure whose Subdiagram Label is visible.
2. Drag a VI or control from the project explorer onto the block diagram.
3. Drag the VI over a Subdiagram Label, then away from it.
RESULT: Object is ready to be dropped until you drag over a Subdiagram Label; after this the object cannot be placed, as though it is always in an invalid location. See attached pictures.
I'm using LV 13.0f2
Very repeatable. Has this been reported?
Thank you, Craig! In the meantime I will practice my flanking drag-n-drop programming strafes on block diagrams protected by bulwarks of Subdiagram Labels!
Sorry for the delay, I was out teaching for a while.
I have filed CAR 449383 documenting this issue.