Change width of scroll bar to make wider. Too narrow for disabled users.

The scroll bar in the TO window is very narrow. My wife is disabled and has poor mouse control, so she is always in danger with the TO window of the mouse straying onto the 'trash' icon. She's always worried about deleting nodes or tabs by accident. I tried changing the scroll bar width both by editing the Windows registry, and also with a Chrome extension (Rescroller), and these can both change the scroll bar width in every window (and Chrome main browser window) but neither affects the TO window (not sure why this is). Can TO be edited somewhere to change this? She does not want to zoom the TO window in, just make the scroll bar wider (and/or move the trash/close icons further away from the scroll bar). Any chance of a solution? Great extension!