move components in 3d view, sticked to the mouse... is blender crazy ?

Hi, i’ve started to use blender as a companion to softimage and i just don’t get why sometimes when i move an edge a point or a polygon, when i releas the mouse this doesn’t end and validate, i have to click and release again to validate my action? Somethimes it works sometimes not, am i crazy ??

Release Confirms option in the User Preferences


thank you very much, it’s hard to find some info on such common search keywords. Sorry for the noise