Some time I have the problem with the vies of the Top Activity Page in the Cloud Control:
The Graf shrink to left and you can see only the part of the picture:
Solution: Restore the zoom of the browser to 100% to display the graph correctly.
And the problem is solved:
Source: EM 12c: Target Database Top Activity Graph in Enterprise Manager 12c Cloud Control is Distorted or Shows a Partial Image (Doc ID 2057382.1)