I use a touchpad on my laptop, and use the two-finger multi-touch scroll. If I flick it, the scrolling possesses it's own inertia or momentum, and the window will continue scrolling. I also have yakuake bound to Ctrl+space. If I scroll with the touchpad, then immediately change to yakuake, the inertia of the scrolling acts with the holding of Ctrl, making the current page zoom (i.e. the same effect as ctrl+scroll).

Ideally, the scrolling inertia should only apply with the initial modifier key (i.e. no modifier), and to the original window. This may be difficult to implement, so perhaps it'd be easier to just stop passing the scrolling action when a modifier key is depressed.

Reproducible: Always

Steps to Reproduce:
1. scroll quickly with the touchpad
2. stop scrolling, then immediately hold ctrl

Observed Results: Ctrl+scroll is passed to the window.

Expected Results: Either scrolling should continue (with no zoom), or scrolling should stop when the modifier key is pressed.

Tested in Linux/KDE.