Hi there
Perhaps try the following?
Inside RoboHelp, click Tools > Options > HTML Editors
tab. See if RoboHelp WYSIWYG is configured as the default.
Assuming it isn't, perhaps that's the issue. Click it and
click the "Set As Default" button.
Assuming it is, try configuring something different as the
default. Then close the dialog. Return to the dialog and reset
RoboHelp WYSIWYG and see if that changes anything.
Hopefully this helps... Rick