Alternative to Tab Mix Plus in Firefox 57 (Firefox Quantum).

So, the much anticipated Firefox Quantum is among us and amazes us with its lightning speed but also make many many people so sad because of the definitive loss of legacy (XUL – XML User Interface Language) extensions support in favor of the new Web extensions. Among the most useful “legacy” plugins I am now missing, Tab Mix Plus is definitely the first on the list.

I can’t believe there’s no way to have multi-row tabs in the new Firefox, i.e. tabs that arrange on multiple rows when their number grows. I think that is an essential feature to many tab-addicted people around here.

I love(d) Firefox because I love customization, which means functionality and productivity to me. A loss on the side of customization isn’t matched by a gain in speed. To say it more clearly, I don’t give a damn about super-speed if I can’t have multi-row tabs.

One might also love Firefox because they say it defends your privacy, but, don’t you see a huge conflict of interest in the fact the Mozilla foundation is heavily financed by Google? I’d personally forget about privacy… Let’s stick then on Firefox’s customization.

I think Mozilla just made a bad move, forgetting what makes really people love Firefox and trying to compete with Chrome.

I’ve already wasted enough time trying to find a real alternative extension to TabMixPlus, so I can tell you there’s no extension at the moment offering multi-row tabbing in Firefox. In addition to that, it seems that a web extension version of Tab Mix Plus is under development but there isn’t no estimated release date yet.

Now, what we can really do for still managing a lot of tabs in our Firefox browser, after the arrival of Firefox Quantum? Here you are some suggestions:

1: stick with an older Firefox. Firefox ESR (Extended Support Release) will support legacy extensions at least until June August 2018.

2: CSS trick. Try adding this to userChrome.css:

.tabbrowser-tab {
    flex-wrap:wrap;
}
.tabbrowser-tab,.tab-background {
    height:29px;
}
.tab-stack {
    width: 100%;
}
.tabbrowser-tabs .scrollbox-innerbox {
    display: flex;
    flex-wrap: wrap;
}
.tabbrowser-tabs .arrowscrollbox-scrollbox {
    overflow: visible;
    display: block;
}
.tabbrowser-tabs .scrollbutton-up,.tabbrowser-tabs .scrollbutton-down,#alltabs-button{
    display: none;
}

The code above gives you multiple-rows tab arrangement, but has the side effect of severely compromising the ability to drag/move tabs. In order to have at least the ability to move a tab in first or last position, you can install the tabsmack web extension.

I advocate the idea that multi-row support should be natively featured in Firefox, but apparently that would be a disruptive change in its UI design.

Update: 29-12-2017

I’ve been using Tree Style Tabs for a couple of weeks or so (thank you Roland for the suggestion!). Though this is a very well written web extension for managing tabs, I’m afraid it doesn’t quite offer the multi-row tab experience I’m missing from pre-quantum Firefox.

So, I’ve eventually decided to pass all my Firefox browsers (I use mainly portable editions) to 52 ESR version and continue to enjoy Tab Mix Plus and other legacy extensions.

My tip to accomplish the conversion from Firefox 57 portable to 52 ESR:

1. first install Firefox Portable 52 ESR. Important: do NOT launch it after the installation! That’s because we don’t want profile folder and files to be created.
2. copy all files from the fresh portable Firefox 52 ESR installation folder over the portable Firefox 57 folder, overwriting all files (of course it’s advisable  to do a backup first!)

This way I hope I can continue to use my favorite extensions at least until August 2018 , when Mozilla has announced it will definitively drop “legacy” extensions.

In the meantime, let’s check Firefox market share and see how bright the new era of Firefox will be.