Tooltip hover popup causes black screen

When hovering the mouse over an icon and the tooltip comes up, a full screen black window appears, but can be removed by clicking any where. The tooltip appears for a brief moment, but then the black window appears. If clicking the 'X' in the corner, it closes WinSCP entirely.

WinSCP version: Assuming 5.15.3 (no apparent way to check)
OS: Windows 10

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