Speaking of which, you might already have your mouse buttons assigned as some hotkeys. Might want to check your mouse settings under the control panel (or Logitech menu).

It's possible you setup hotkeys on the mouse for some other software, but put settings on a global menu rather than a per-software menu.

As for something that might cause behavior like this in Blender? The one I could think of is "Auto Perspective" in prefs, if it's on try unchecking it.

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Barbequed Pixels?

Your friendly neighborhood Wings3D nut.
Also feel free to browse my freebies at ShareCG.
There might be something worth downloading.