What is the best way to add new custom properties in WebPart Editor Pane of the OOB SharePoint WebParts (such as Content Editor WebPart & Script Editor WebPart which are created as sealed class)?

I've already come across the following articles but it looks like we can add custom properties to only Custom developed Web Parts. I want to utilize the existing capabilities of CEWP or Script Editor WebPart and introduce new custom properties (that can be used from within apps hosted in these OOB web parts).



My main goal is to introduce new custom properties in the edit panel of the OOB web parts. I'll use SharePoint REST API to fetch the property values.

I believe the only to achieve this is to use Client side web parts developed using the latest SharePoint Framework which only on SharePoint 2016 Feature Pack 2 and SharePoint Online. Unfortunately, I'm on SharePoint Server 2013 Standard and trying to figure out an alternate way to achieve this.

1 Answer 1


Unless you use tool such as dotPeek and create own clone of these OOB web parts, it isn't going to work, as you said, because they are sealed and you cannot inherit from them.

Have you considered instead implementing the property value configuration within the apps you host inside these web parts? Or maybe create a "wrapper" app, that contains the logic for managing these properties, renders the property configuration screen within the web part when page is in edit mode, and when in display mode, renders the actual app?

  • Yes...I sort of figured that and I'm using a tool to look at the CEWP source and develop a clone. As far the other options you have mentioned, I did consider them initially before taking this route because I felt they were much better options and easier to maintain. However, my customer is sort of hung up on this CEWP customization for some reason (even though I personally feel that this is just additional work and not the right approach).
    – arut
    Oct 9, 2017 at 9:34

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