Add left/right arrows to decrement/increment by one unit the slider value in "Create custom filter" dialog

[gorhill]

Description

The ability to increment/decrement by one unit the slider value is convenient, especially on a mobile device.

[u-RraaLL]

Are you planning on adding the buttons in the same line as the slider?

uBOL's Picker (full size) takes an unnecessary amount of space. Especially on mobile.

uBO's Picker ~40% of the page, uBOL's Picker ~65% of the page

The selector list's font looks to be bigger than the font elsewhere. That might be on purpose for easier tapping on selectors, I guess, but idk if it's necessary since picker is zoomable.

The more/less line takes precious space, there's also some unnecessary padding above/below the input box and the slider.

Honestly, I'd:

• Put the match counter to the right of the slider, similar to uBO.
• Add the new arrows to the left (this issue).
• Remove the tip about using the slider, when picker is fully expanded.
• Remove the more/less area. Add [ + ] [ - ] buttons next to the [_] minimize button instead. Viewable when not minimized.
• Make the selector list area slightly smaller, make the font smaller too.

As a side note, the arrows pointing down/up in the more/less line don't really make sense in picker since, by default, it's sticky to the bottom and it expands upwards, not downwards like uBO's popup, from where it was copied. That's why I'm suggesting plus/minus instead - applicable wherever picker is moved to on screen.