In order to avoid such undesired behavior when scrolling, the custom GridDataCellElement should be composed only of RadElements. However, the RadWebBrowserElement contains the Windows Forms WebBrowser control, which hosts Web pages and provides Web browsing capabilities to your application. Using controls in grid cells may slow down the scrolling and will cause visual glitches as they do not support clipping.
A better option would be using custom editors. Please have a look at the referred help article. Another option is to use our HTML-like text formatting. In the provided help article, you can find the list of supported markup tags.
I hope this information helps. Should you have further questions, I would be glad to help.
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