renaming the files is not the issue...I know if i highlight a group of files and click the rename button, the dopus dialog pops up. But if i do the same and right click and select rename on the selected files, i get the standard windows rename dialog...
The toolbar button and the context menu run different commands. You can create a context menu option for 'All files and folders' that runs the same command as the rename 'button'. If you go to Settings->File Types you should see 'All files and folders' under the 'Directory Opus File Types' header.
double click on it, and go to the 'Context Menu' tab
select New and in the 'Action' field type a name for the command as you want to see if when click RMB (right mouse button).
in the 'Type' drop down, select Run an Opus function (not supported in Explorer)
in the 'Edit' window at the bottom, paste the following command for starters:
Rename ADVANCED
This should get you started... From here you can also bring up the rename dialog in a defined preset if you find you often use particular rename patterns etc etc.