When you press and hold the tab manager icon in safari, a menu pops up with options to open/close a tab, add it to a tab group, etc. you just flick your finger to the action, you don’t need to lift it.
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Actually Firefox (on Android that is) is almost there: you can long-press the Tabs button (the one counting the number of open tabs) and there is the option to open other tabs or close this one.
Until we get the extremely important Tab Grouping feature, long-pressing on the Tabs button (or the 3-dots button) and moving the finger on the screen to basic actions (i.e. Back, Forward, Share, Refresh) should be implemented. I've heard that on Android, Opera is already doing it.
And even better yet, let's hope we would be allowed to customize the actions!