Comment 440 for bug 263435

Amidst the lots of comments I found out that they already decided on solution: https://wiki.mozilla.org/Plugins:AdvancedKeyHandling

If I understand it correctly, this means the plugin will decide (after it will be updated for new API) whether or not pass the key. Can't say I like this solution; seems unnecessary cumbersome, and non-standard shortcuts could not work (what if it'll be another browser with different shortcuts, or is this API for Firefox only?).