I'm on a WAMP so I can't share, but I just installed Bootstrap 1.2 and all the widgets in my custom widget area disappear. If I then attempt to replace them, they again disappear the moment I refresh the Admin page.
I created this custom widget area in a child theme using this code:
This was working using the exact same setup/code using Toolset Bootstrap 1.1.
If I change my child theme's parent to Twenty Fourteen instead, the same setup/code works again, but the moment I switch back to Toolset Bootstrap 1.2, the problem comes back. Note, I do not use any plugins other than TVC plugins, I have tried every variation of name (no big caps, no spaces, etc.), but can't find a fix.
Thanks for your speedy and helpful response. The function associated with this filter appears to contain a lot of checking and setup re: widgets. Is there anything I should expect to malfunction given the removal of this filter?
May I ask why this hasn't been addressed in 14 months since it was reported? I just wasted an hour trying to get to the bottom of this and only did because (I assume Wayne or Willem) posted this on wordpress.stackexchange.com.