I noticed that I recently lost the ability to use the 'check all' checkbox throughout the wp-admin interface, for example when I wanted to select all plugins and disable or select all posts and bulk edit.
It looks like this is caused by Toolset forms Version 2.6.21. If I turn off all plugins and revert to the default wordpress theme, all I have to do is activate Toolset Forms and I lose the ability to 'select all' (posts/plugins/etc) throughout wp-admin.
Could you please update ALL Toolset plugins to it's latest officially released version. You can download the latest plugin release from your account's Downloads page:
=> https://toolset.com/account/downloads/