The Firefox address bar, location bar, URL bar could be better.
It is not possible like in Opera Browser to easy select specific text.
In FF only 2 modi are present: all or nothing.
In Opera there are 3: all, nothing, text/additional characters.
When working often with copying parts of URLs it would help a lot to have this option also in FF
Do you mean using a mouse on a desktop version of Firefox? You should be able to select what you like, but you may need to click an extra time to clear the initial selection. (If you are trying to double-click to select a word, you may need to pause to avoid triple-clicking to select all.)
Also, you can look at these preferences in the Config editor:
browser.urlbar.clickSelectsAll (default is true)
browser.urlbar.doubleClickSelectsAll (default is false)
I think it’s less convenient on the Android products but I don’t do it often enough to start a new thread.