Bug in photoshop background, can't move around canvas with hand

[#1]

Hello,

Here 's the picture of the bug : I tried altering display preferences . No go . Might it be because I work with an external PC monitor and occasionally unplug it ?

Any suggestion  welcome.

Kal

[#2]

Hello,

Here 's the picture of the bug : I tried altering display preferences . No go . Might it be because I work with an external PC monitor and occasionally unplug it ?

Any suggestion  welcome.

Kal