Do you really mean ScrollLock? AFAIK VisualStudio does not change behavior in response to ScrollLock.
I suspect you are experiencing that VS incorrectly assumes that one or more of your modifier keys is held (ctrl, shift alt). To fix this, press and release each of the modifier keys in turn, while VS has focus.
Real example:
The application I'm debugging has focus, and I hold the ctrl key for the in-app function when I suddenly hit a breakpoint, giving VS focus. However, VS did not seem to register that I issued the Ctrl key, so my first attempt to scroll through a document with the mouse wheel changes my dpi value ... (ctrl + wheel = zoom)
Fix:
Press and release the modifier key when VS has focus.
James
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