This may seem a bit weird, but I am certain that I remember reading that doing this (as well as the opposite, holding leftclick and pressing rightclick) has a function of some sort, I just can't figure out what it is, and I searched through the list of shortcuts and throughout the manual, to no avail. I do know that you can sort through stacked markers using left click + right click instead of tab, but it was something else than that, unrelated to the time ruler. Anyone knows about this? Driving me nuts at the moment.

Spencer I am certain that I remember reading that doing this (as well as the opposite, holding leftclick and pressing rightclick) has a function of some sort, 

YES! You will receive a recorded message saying…
 
As always, should you or any of your IM force be caught or killed, the Secretary will disavow any knowledge of your actions. Good luck, Jim. This tape will self-destruct in five seconds. 

Hold down right button and left click undoes last zoom action. Other way round redoes it.
 
HTH

ahh that's it! thank you so much, I can now live a normal life again.