Pop-up window for debugger values will occasionally bring up an empty standard dialog

When navigating code with the debugger active, you will occasionally get an empty dialog pop up instead of the normal pop-up window for debugger values. Attached is a screenshot of the dialog. This shows up on the task bar as a separate window, and must be manually closed. (i.e. moving the mouse doesn't automatically close it like the pop-up window for debugger values usually does)

Steps to reproduce:

1. Run a project in the debugger and break.
2. Mouse over a token that doesn't have a value associated with it. For example, a type name or function call. Wait a bit for the standard delay to show the value pop-up.
3. Scroll the code window with the mouse scroll wheel or trackpad. At this point, the empty window should show up.