Vff images gui not working

ive been all afternoon trying to work on the vff exercise but the vectors gui and the camera image dont seem to refresh. they work a few second some times and suddenly. but if i open the gazebo simulation everything is working well and the robot is moving. it is very difficult to work like this

Good morning,

Are you working in the local backend or in the remote backend? We have tried the remote backend and everything seems to work.

Best regards,
David