I'm noticing a significant decrease in object speed when I switch to fullscreen mode. I'm changing a panel's position by adding one pixel to pos_x/y when the user presses corresponding keys. I'm thinking that since there are more pixels in fullscreen mode vs. 800x600, movement by one pixel at a time would take longer in the former. Is there a way to make an object move the same between different screen resolutions?

use time_frame and/or time_step (see helpfile)

Thankyou. I set fps_max and fps_min to the same value and for pos_x/y I did, pos.x += 1 / time_step; This gave me the desired result for both 800x600 and Fullscreen mode.