In TeleScope versions prior to Executive 2020.1, Firefox would freeze up when sharing a collection via My Collections > Click on i button for a collection > Edit Sharing > Select User(s) > Ok. This problem exists for Firefox(confirmed till version 82) on Windows and Mac OS but Chrome works fine for the same operation on both OS. This article discusses what causes this issue and a fix for this issue.
Steps To Fix
This issue was fixed in TeleScope Executive 2020.1 and it is recommended to please upgrade your TeleScope version to this or later to fix this issue. If your TeleScope installation has customizations or you're an OnDemand customer, please contact your Account Manager or support for help with upgrading.
After upgrading TeleScope, log in to it in Firefox and try to share a collection with another user via My Collections > Click on i button for a collection > Edit Sharing > Select User(s) > Ok. After clicking Ok the operation should finish in a few seconds in Firefox.