Editing a Frame - Selection Handle is not selected

2.0 Beta 1, Windows 8.1 desktop

Edit a horizontal or vertical frame by:

(1) double-clicking on it; or

(2) selecting it and choosing Edit Element (Ctrl+E) in the context menu.

The selection handle appears as a transparent square instead of the customary blue one.

Attempting to resize a horizontal frame (with Ctrl + arrow keys) seems to work correctly, but the same action causes an erratic and incorrect response with a vertical frame.

Workaround: click the transparent box with the mouse, and it turns into a blue box.