Add option to hide X from tabs on sidebar

[J-PIE-314]

After using the new tab sidebar for a while I have found that the X (close tab) button is annoyingly easy to accidentally click when attempting to switch tabs, especially when a volume button is covering part of the tab icon.

Could there be an option to hide the close button. I can still close tabs by middle-clicking on the icons or using a keyboard shortcut.

[sirex]

In 30-40% cases instead of clicking a tab I close it, because (x) suddenly appear.

Either option is needed or some logic, .e.g when width is minimized do not show close button (x).

[Fernst]

Has an option been implemented? Realistically, how difficult is it to implement it for Firefox developers - 10 minutes, or more?