This bug seems to be related to the toggle switch. The UI elements are not shown (when using the default elementary OS theme) if there is a toggle switch in the window AND it is in the "On" position. If it is switched to "Off" then everything appears as normal.
This bug seems to be related to the toggle switch. The UI elements are not shown (when using the default elementary OS theme) if there is a toggle switch in the window AND it is in the "On" position. If it is switched to "Off" then everything appears as normal.