Insert both characters if a dead key combination is not recognized (e.g. ‘a → á, ‘b → ‘b)

When I use any variation of English, US international (with dead keys,altGr dead keys or alternative) on my Linux Mint machine I always encounter this behaviour.
When I press one of these keys: ' " and then follow them with a ‘non-accentable’ character like a [ or a b no output comes out at all.

Unable to simulate Ctrl+Shift+Fn+F10 Key press

I have an ubuntustudio 16.10 64 bit on an IBM Thinkpad E431. I am able to launch an app from a shell script, but the next step involves pressing Ctrl+Shift+F10 On my notebook I need to press the button Fn before F10 . I use xfce Desktop. I am unable to simulate this in a shell script. I had also disabled my touchpad but did not help.