If you have Captivate 4, perhaps try clicking Edit > Preferences and disabling the Capture interim screenshot option?
Aside from that, I would recommend liberal and judicial use of the Capture keystroke. Normally it's the Print Screen key. But you are able to change it.
Helpful and Handy Links
thanks for the help but that setting regretably did not do the trick. I usually make manual screenshots with the print screen button in abundance anyway, but I thought there might be a general solution for the highlighting effect because anybody who records standard desktop apps will run into the problem. Maybe it is even possible to supress the highlighting in the Windows settings but I have not found the control for that yet.
Thanks for the link! I have completely overlooked the possibility of regisrty hacks - maybe there is a setting to suppress the menu item highlighting as well Suppressing the tooktips is a nice option in itself, I´ll definitely use that option too.