Editing a normal widget and a HubNet/SDM widget at the same time causes a visual bug

Minimal steps to reproduce the bug:

1. Open HubNet Client Editor
2. Create a widget in the main interface and leave the edit dialog open
3. Create a widget in the HubNet interface and leave the edit dialog open
4. Cancel the edit dialog in the main interface
5. Cancel the edit dialog in the HubNet interface

The expected behavior is for step 4 to close the main interface edit dialog and remove its associated widget, and for step 5 to close the HubNet interface dialog and remove its associated widget. However, although the edit dialogs close at the correct times, the main interface widget itself is not removed until step 5 is completed. This works the other way around (HubNet first, then main interface) and with SDM in place of HubNet.

I don't have many leads at the moment, but it seems like the second edit dialog somehow blocks the first edit dialog's event queue, preventing it from returning from its setVisible(true) call until the second edit dialog is closed.