Input gets eaten during right-click scrolling

[Simon]

CE 1.0.1
NL 12.14 and other versions from years ago.
Wine 10.6

• Start a level.
• If it's a small level, zoom in until you can scroll.
• Scroll with the hold-to-scroll feature. E.g., map this to the right mouse button in NL's options, then scroll by holding the right mouse button.
• While you hold-to-scroll, press a skill hotkey to select a different skill.

Observed: You have a ~50 % chance to select the new skill. Otherwise, the skill key has no effect and the old skill remains selected. (The hold-to-scroll will always continue to scroll correctly, whether the new skill selects or not.)

Expected instead: The new skill gets selected for certain. (And the hold-to-scroll will always continue to scroll.)

-- Simon