previewing video in a GUI

HI....I have a GUI that has one axes and three push buttons:Start Camera,Capture and Crop.

the 'Start button' starts a video object and creates video preview in the axes.it works fine.

After pressing the 'Capture' button..the current frame in the axes is displayed while stopping the video object.

i can restart previewing video by again pressing the 'Start Camera' button.

i crop the image by pressing 'Crop' button(using 'imcrop') and display it in the same axes

but when i try to preview the video by pressing 'Start' button again ,it doesnt work..May be due to the change in axes resolution due to cropping...I cant get it work...I have to close the GUI and start all again.

kindly help.....Thankx in advance!!