Restoring the Roll20 delete prompt/warning

I ran into this issue trying to delete recently uploaded images from my Library in order to reclaim some storage space on my account. I was able to delete each file one at a time but a window popped up with a check box for Roll20 not to prompt you and warn you that deleting can't be undone. I clicked the box. Now I can't delete ANY of the recently uploaded files. I can't figure out how to uncheck that box. Has anyone else run into this problem?

What happens if you delete all Roll20 cookies?

I don't know...I don't even know how to find my roll20 cookies. :)

If you are using Chrome: On your computer, open Chrome. At the top right, click More . Click More tools. Clear browsing data. At the top, choose a time range. To delete everything, select All time. Next to "Cookies and other site data" and "Cached images and files," check the boxes. Click Clear data. You may wish to enter "roll20.net" in the filter box in step 5 before proceeding to step 6. If you are using a different browser, the procedure is similar, just Google "how to delete cookies on {browser name]". Post back and let us know if this fixes the problem.