Context menu on root node of project tree does not display correctly

The context menu on the root node of the project tree does not display correctly on macOS.   All the other context menus on other tree nodes appear to work fine.

On first bringing up the menu what looks like a native macOS window border (rounded corners, drop-shadow) is shown occupying the same region as one would expect to find the context menu. No content has been painted to this window at this point, so it appears transparent. (First attached image).

Moving the cursor down through the menu area causes some, although not all menu entries to be painted. (Second attached image)

The third attached image show all entries which get painted after moving down through the menu.

A possibly related problem is that it can be difficult to get this context menu to appear at all. Sometimes it appears very briefly, then disappears. In fact, while I was reproducing the issue for this report it because increasingly difficult to get this menu to appear, until I couldn't get it to appear at all.