Putting the transmission in any of the synchronized forward gears stops all the motion in the transmission. Quickly selecting reverse before the gears have time to spin up again is a good work-around, but if the problem persists, you might have a little bit of drag of the clutch disc against the flywheel or pressure plate. A slightly tight pilot bushing will cause the same problem, keeping the input shaft spinning just a little, even with the clutch pedal fully depressed. Reverse is the only gear that's not synchronized.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!