Error using selection tools

[jorgeb45999191]

When I make a selection using the lazo or quick selection tools, part of the image outside the selection is occluded. I can restore it clicking several times over that sector. I'm using the last version of PS in a mid 2011 iMac with High Sierra as the OS. I'll very much appreciatte any ideas to fix this.

[c.pfaffenbichler]

Could you please post a screenshot with the pertinent Panels (Toolbar, Layers, Channels, Options Bar, …) visible? 

Does turning on (or off, depending on the current settings) Photoshop > Preferences > Performance > Legacy Compositing and restarting Photoshop have any bearing on the issue? 

Does turning off »Use Graphics Processor« in the Performance Preferences (Photoshop > Preferences > Performance > Graphic Processor Settings) and restarting Photoshop have any bearing on the issue? 

[jorgeb45999191]

 That's what I see after using the lazo tool. I've modify Preferences as you suggested, but doesn't solve the issue, Thanks for your help

[c.pfaffenbichler]

Did you restart Photoshop after turning off Legacy Compositing? 

[jorgeb45999191]

Yes. Everytime I modify anything in the program.

[jorgeb45999191]

I solve the issue, just by turning off the ruler : View > (cmd+R). Thank you very much for your help

[c.pfaffenbichler]

Again with the Rulers? 

It’s impressive how many issues they have been involved with by now … 

You may want to post a bug report over on 

Photoshop Family