If the functionality is missing anyway - why using up space in the WebUI?

[stumbaumr]

The Smart EQ does not allow start and stop charging. Instead of displaying an error message after pressing the buttons, the buttons should just not be there at all using up precious space on my display.

Maybe it also keeps users from asking unnecessary questions...

[dexterbg]

The web UI mostly doesn't know about individual vehicle capabilities yet, because the old V2 capabilities framework wasn't sufficient for V3 and a new framework hasn't yet been designed. This needs to cover capabilities added by plugins, as these may implement functions missing from a vehicle.

For example, the Twizy can only stop a charge, so starting is often mapped to a smart plug activation. Other vehicles missing charge control altogether may map the start/stop actions to wallbox control commands.

If you'd like to work on the V3 capabilities framework, begin with reading the posts on this topic on the developer list.
https://lists.openvehicles.com/archives/list/ovmsdev@lists.openvehicles.com/