Layout widget in editor is now scrollable

[Semphriss]

Having dozens of tilemaps and other sector elements is no longer a pain to manage - now you can scroll the toolbar and access those sneaky little icons!

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Urgh! I can't access all my tilemaps! They're going off-screen!

Ah, much better.

[serano01]

Awesome, especially for the forest worldmap, since it has so many tilesets.

[Zwatotem]

Looks good, but I would block it from further scrolling if there's only one icon left on the screen. Currently you can flush them all to the left.
Btw, I expected mouse scrolling, by the title, maybe I expected too much 😆.

[tobbi]

Approval from me once the review comments were addressed.

[tobbi]

Oh, and check the travis warnings and fix them.

[Semphriss]

I'm gonna fix all of this, I'd just have one question :

Btw, I expected mouse scrolling, by the title, maybe I expected too much.

I'm not sure to understand... It scrolls by hovering the first or last 32 pixels of the widget bar, isn't that the way it should work? I wanted to make it work the same way as the tilesets widget. Do you want me to make it another way? What's the method you originally understood from the title?

[Zwatotem]

Sorry, my comment didn't make much sense. What I had in mind was mouse wheel scrolling, just like the tile selection panel does, but horizontally.

[Semphriss]

Oh, okay. Should I also make it scrollable with mouse wheel?

[Zwatotem]

If it isn't much of a deal for you then sure.

[Semphriss]

I'll look into this; I'm pushing my first fix batch in a few moments, I'll use that first batch to see if there are any other Travis errors.

I'll add the mouse wheel scroll (if doable in less than an hour 😆) in the second next commit, along with any other Travis errors if applicable.

[Semphriss]

Alright, I couldn't resist and I did everything in a single commit.

I do have a problem, though; scrolling with the mouse wheel also triggers the editor behind the widget. It seems like my return true; in the mouse wheel function isn't enough to prevent propagation.

[Semphriss]

Nevermind, it's a code 18. It works fine now, and I fixed all the requested changes; I'll commit now.

[Zwatotem]

There is an unintended behaviour in that new feature, the bar keeps scrolling, even when I take the mouse.
See video:
https://youtu.be/BV5S4DYmnbU