Lifting ctrl and fn keys at the same time while tapping an arrow key rapidly, can cause keys to become stuck

[Andrew Hayzen]

I'm in a terminal and I usually use Ctrl + Arrows or Home/End (which on my keyboard are Fn+Left Arrow and Fn+Right Arrow), however when pressing a certain key sequences quickly together the keys can become stuck, forcing the cursor to one end of the terminal. Also note it is not just related to the terminal, the cursor is forced to one end of any input within the scopes or other apps

What happened:
1) Focus a text field with a few words in it
2) Press and hold both Ctrl + Fn
3) Tap the RightArrow rapidly
4) While tapping release Ctrl + Fn together (keep tapping the RightArrow a bit longer than the ctrl + fn - up to a second longer)
5) Sometimes the cursor will jump to the right of the field and is 'stuck'
6) Depending on timing of lifting the keys at the same time, you then have to press Fn+RightArrow or Ctrl+RightArrow to make it 'unstuck'

Note: this is down to timing so doesn't always happen

What I expected to happen:
At #5 for the cursor not to become stuck due to the system thinking the key is pressed.

[Andrew Hayzen (ahayzen)]

Not sure where exactly in the stack the error is, but it only happens under unity8 (not unity7) so adding Mir + Unity8 to the bug.

[Michał Sawicz (saviq)]

Syncing task from Mir.