Please help us help you and fill where relevant:
Your LimeSurvey version: 5.6.3
Own server or LimeSurvey hosting:own
Survey theme/template: vanilla
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Hi,
we want to disable the video buttons in the ckeditors toolbar globally and inserted a line in  the config.js (assets/packages/ckeditor) with a.removeButtons = "Html5video,VideoDetector"; but without luck. Is there a way to disable video buttons?
Thanks a lot,
jim
 

we need to remove tabs too from the popup windows. Is there a way on doing this? Thanks!

we want to disable the video buttons in the ckeditors toolbar globally

You can hide it with CSS in a custom admin them rather than editing core files which will be overwritten on updates.

Create a custom admin theme - www.limesurvey.org/manual/Custom_Admin_T...y_Version_3_or_newer

Place this in the custom.css file of that theme:

we need to remove tabs too from the popup windows.

Open a new thread for that and provide screenshots (we have no clue what you are referring to.).