The difficulty may be related to the context of a pop-form, rather than a simple web page.
Is that a publicly accessible resource that we can look at ?
If not, it's possible that you can get the XPATH to the control by:
- Ctrl click it
- Choose 'Inspect' from the contextual menu
and then in the webkit source view,
- Ctrl-click the highlighted source element for the control
- Choose Copy As XPATH from the contextual menu
It may then be possible to find a solution using some the XPATH resources and sample code on this forum from an Execute Chrome JavaScript action, or, perhaps more simply, from a custom action like:
Again, however, it is possible that the popup form context would need some additional special handling - hard to tell without seeing the page itself and the way in which its source code is written.