Plugins development about fetch table information

[Xiaoduan Chang]

I recently have a problem while developing a plugin. What I wanna do is to get the information about the columns of a particular table and show them up in a window.

I try to use wbinputs.selectedLiveTable() as input. However, after I install the plugin, the option in the menu is gray and I can't click it. What's happening here? What I should do to fix it? Or is this the right way to handle the problem?

By the way, where can I find more useful document about plugin development? I've visited the official blog and read through the passage there. I've browsed the source code in /usr/lib/msyql-workbench/modules and found nothing useful.