NPAPI mac plugin shows unresponsive message in Chrome when opening context menu

Question

I'm working on an NPAPI based plugin, and have been observing an issue when opening the context menu in Chrome, displaying an error message saying that the page is unresponsive after leaving it open for 30 seconds.

I've observed the same issue with Flash Player 10.3 (which uses NPAPI, 11.x versions uses PPAPI).

Also, this issue only happens with Chrome, and trying to open the context menu when we aren't in the mouse down event takes no action, and no menu gets visible.

Any thoughts?

Thanks, Rodrigo.

Answer 1

This is simply a bug in Chrome's NPAPI plugin host on OS X.

Answer 2

The reason why this happens is that you must not ever block the main thread, and when you have the menu open you're blocking the main thread. Since the main thread is blocked, the plugin doesnt' communicate back to the browser process and the browser process detects it as being frozen.

The only solution I can imagine would be something that lets you do what you need on an alternate thread. Chrome will always display that notice if you block the main thread, no matter what you do.