first to explain why you get this error: the file viewer widget is created with an old version of how you can create widgets in Mendix which is based on the Dojo framework. Sadly widgets from this version are not compatible with the new version of creating widgets which is based on React. That means that you cannot put any Dojo widgets inside React widgets. So there is not a direct "fix" for this.
You could check if a different widget might be a solution for you, I saw this one in the marketplace which might work but I havnt tried: https://marketplace.mendix.com/link/component/116214
The other option is to find a different solution to his where you either dont use a datagrid 2 or you use a popup or something else.
Hopefully that helps
@chenga shaobo
I have implemented those points which you have mentioned in previous email, but still I'm unable to access UFV button there.
Here I am trying to download this addon but still the issue remain same, I went through this widget " TOF PDF Document Viewer" , trying to download from market place but there is some version mismatch issue so we can't able to download.