Florence stays out of your way when you don't need it: it appears on the screen only when you need it. A timer-based auto-click input method is available to help disabled people having difficulties to click. You may also check the new efficient ramble method.
I'm going to buy a tablet and put Linux there. Maybe I will install this virtual keyboard. I think it will be convenient.
Installation into Linux Mint:
sudo apt-get install florence
Installed on the Mate desktop environment
Remove from Linux Mint:
sudo apt-get remove florence