Uncaught TypeError: wp.template is not a function

Sorry to hear you are encountering an issue with Custom Sidebars. It looks like a conflict with another plugin. Try deactivating your other plugins so just Custom Sidebars is running. If this fixes the widgets area please reactivate your other plugins until the error returns. You can also try switching to a default theme to see if conflict is with your theme.

Let me know how this goes.

Thank you for using Custom Sidebars. I am going to mark this topic resolved because we haven’t heard from you in awhile. If this issue was not resolved we can reopen it. Thanks again!

If anyone else is having this issue, look carefully at the error as displayed in your web browser’s developer tools console. It should say something like, Type Error: wp.template is not a function but following that it should then say where the error is, and perhaps show a call stack (depending on browser).

Look at the path given in the error. It should say something like:
…/wp-content/plugins/OFFENDING_PLUGIN_HERE/….js:###:##
where the first ellipsis is your website WordPress Site URL, “OFFENDING_PLUGIN_HERE” is the subdirectory name of the offending plugin (which is usually close enough to its displayed name to tell you which it is), the second ellipsis will be the path from there to the actual offending .js file (this is a JavaScript error, not a PHP error, so would appear in a .js file or some other extension containing JavaScript / ECMAscript code), and the “###:##” are the line and column numbers (respectively) where the offending wp.template() call is.

For now, once you know which plugin it is, you can simply temporarily deactivate it to allow full functionality of Custom Sidebars or other plugins that it’s interfering with, then re-enable it if you truly need the functionality of the offending plugin.

But don’t forget to also go to the support page or website of the offending plugin and let its maker know about this. Copy-and-paste the message from your developer tools console (you can and should delete the stuff before /wp-content for site security reasons — they don’t need to know that), and also a few lines from the code itself in the section containing the erroneous wp.template(…) function calls, copied from the debugger pane of your browser development tools.

I’m about to do just that with the Ecwid Store plugin, which is causing similar issues with PressCustomizr’s Customizr theme.