hmm, you should be able to hide the keyboard through the "hide keyboard" button on VK. The expected behavior of the keyboard button in the tray is to show VK, not toggle the visibility IIRC. But I can see why you want it to toggle the visibility. Let me cc VK's pm +tbuckley and see what he thinks.

I'd expect it'll simply move the VK to that display, instead of toggle, although other people may have different expectation.

It seems like the user would want to move the virtual keyboard to the other display in that case. It seems rare that a user would want to close a virtual keyboard from a secondary display.

Per offline discussion - yhanada@ will have the button click act as if the user wanted to open the keyboard on that specific display.

I confirmed that the button click already works as described in comment 3 and 4.