Sorry to hear that the add-on wasn't working properly for you.

On some systems, the scrollbar colors may be overridden by the operating system itself. In that case, there is a setting that can be disabled in Firefox to allow the Custom Scrollbars add-on to change the colors. See this for more information: https://github.com/WesleyBranton/Custom-Scrollbar/wiki/Scrollbar-customization-is-not-being-applied

Glad to hear that you like the add-on.

Unfortunately, there are some websites (Twitch is a good example) that have taken scrollbars a step further. Instead of using an actual scrollbar, these websites have designed custom components that look and behave similar to scrollbars, but they are fully custom. Since these are not actually considered "scrollbars" by the browser, it's not currently possible for me to make any modifications to these scrollbars.

As for the transparency issue, some websites have not set the background of the page (meaning it stays white) and instead have a large panel that they have set to be the width of the screen. The width of the screen does not include the scrollbar, so the white background hiding below shows through. Much like the issue above, there's no way for me to fix these either.

Hi James. Sorry to hear you had issues with the add-on.

As far as the scrollbar buttons go, currently Firefox only supports limited scrollbar customizations. That only includes colors and very limited width settings. As Firefox adds more features (which I hope they do), I will be able to add more functionality.

As for no visible changes being shown, it's important to note that there are some pages the add-on cannot make changes to. These mainly include internal browser pages (settings, etc.) and pages that are generated by other add-ons. For more information, see: https://github.com/WesleyBranton/Custom-Scrollbar/wiki/Pages-this-extension-cannot-modify