Extjs is deprecated and might be fully removed in the next major release of AEM. I would recommend using Coral UI. You should be able to use most of the coral UI components within a touch UI dialog. Let me know if you are running into an issue with a specific one.
I am trying to convert classic UI dialog to touch UI. As the modernization suite provides conversion of basic components from ExtJs to Coral, I wanted to customize it by adding additional components conversion capability.
I wanted to understand what are the possible components that can be included in Classic UI, so that I can try out the conversion or customize the modernization package accordingly.
To take an example, could you help me how CheckboxGroup component be used inside a Classic UI and the relevant Coral UI component. Also is there any document that lists possible ExtJS components eligible to be used inside Classic Dialog?