[css-transitions] 'display' influencing transition of other properties

[SebastianZ]

display obviously has influence on the transitions of other properties and I'm wondering why that's the case. I.e. when the display value is changed on the transitioned rule, also the other properties are transitioned in a discrete way instead of respecting their related transitions.

I've created a simple example at CodePen illustrating this.

I can't seem to find anything in the spec. explaining this. Is that an implementation bug?

Sebastian

[birtles]

This was brought up here: https://lists.w3.org/Archives/Public/www-style/2013Jun/0562.html
With the most helpful explanation being: https://lists.w3.org/Archives/Public/www-style/2013Jun/0569.html
cc @hiikezoe

[SebastianZ]

In #8174 we got a @starting-style rule which obviously covers the described use case.

In that issue it was claimed that display: none does not create a before-change style.

Currently, the related spec. text reads like this:

If an element is not in the document during that style change event or was not in the document during the previous style change event, then transitions are not started for that element in that style change event.

The phrasing "not in the document" seems at least vague, though, and doesn't reference what it means by "document". CSS Display 3 rather refers to "boxes" and the "box tree" and says that none doesn't generate any boxes.

So I believe both should refer to the same terminology if display: none is meant to not start transitions in style change events.

Though, of course, it would be even better if transitions of other properties were not affected by the value of display.

Sebastian