I don’t remember since when it is a part of Appearance, but it was not always like this.
And I know about this strange behaviour you demonstrate in the video below.

Here is the thing (and I suppose it should be changed): you can drag the fill only when when the swatch in the item is in focus... in 'double' focus — and this is stupid. See, when you click an appearance item, it gets highlighted with blue, and the swatch (or rather a square that is filled with a color or pattern) gets
enlarged. But these two events are not connected! Start dragging an item by its blue bar, as if you are going to change the the order, and as soon as the cursor crosses the border, the square gets un-enlarged... and stays like if you release the mouse. And while it’s stays 'half-selected' like this — you can’t drag and drop it over an object on the canvas... So every time you start dragging an appearance item by the bar, it gets unselected. The only way you can drag it out to drop is to grab by the square... and only when it’s enlarged, so you have to click it again if it’s not before dragging... ridiculous, I know. And you can’t change an order of items by dragging a square (or an arrow on the left).

Why the team decided to distinguish between 'order' and 'apply' operations, giving them different areas for grabbing — I have no idea. They don’t intersect, and totally would be easier to perform if it didn’t matter where to click.

Then, there is a trick. While dragging a fill you can hold Shift before dropping and apply a color you drag as a stroke instead of a fill... but the hint displayed if you wait says about 'alternate UI', which is actually about Shift-clicking on a a square to bring Color pseudo-panel instead of Swatches (and actually thay should have said exactly this and not 'alternate UI').

Finally, as you mentioned, there is no way to add a dropped fill/stroke as a new item. You can held Alt, but it changes nothing. The 'operation slot' exist, but they just don’t use it.

It all should be addressed.

(Apr 19, 2011 12:36 PM: https://forums.adobe.com/message/3024807#3024807)

Wow, its works in 2019 Ai 23.01.

but very unpredictable for filling.
I can not move stroke.
You can not add new apperance to existing ones. You can only exchange basic ones.

Is this a mistake? Since when does this functionality exist in Ai?

https://vimeo.com/305953068

Apr 19, 2011 12:36 PM

https://forums.adobe.com/message/3024807#3024807