Sorry for the late reply (9 months, LOL), but here's an answer to your problem, in case you haven't figured it out or someone else comes here with the same problem. :)
When using v1, you can open the "Settings" page and hide the resize tooltip ("Tooltip visibility"). Then, you can (optionally) open "chrome://extensions/configureCommands" and add a keyboard shortcut for the "Show/Hide tooltip" command, so you can manually enable it only for certain tabs.
In v2, the tooltip is not showing on all pages by default (although it can be enabled to do so) and you can set a keyboard shortcut or toggle it from a dedicated button found in the extension's popup menu.
Customer support service by UserEcho