Z-index bug with calc()

[Nico3333fr]

Hi there,

I'm Nico, a dev working for ProtonMail.

Some of our users reported an issue in ProtonMail with PaleMoon (Linux), basically some modals are not working because the overlay is on top of modal content (and it should not obviously).
This does not happen on other browsers like Chrome/Firefox/Edge/Safari.

I did try to reproduce with last version on Windows (29.4.4), I was able to reproduce.
After a few tests, I isolated the issue on a simple test case here: https://codesandbox.io/s/pale-moon-z-index-calc-jqbhf

The issue appears when calc is used in z-index property, as you can see .

Is it possible for you to fix this CSS issue in Pale Moon - supporting calc in z-index, so everybody can be happy?

If any question, do not hesitate to ask.

[Moonchild]

Thanks for reaching out, Nico!

Our support for "in-line" calc() in css keywords is limited at the moment and z-index isn't yet supported (since our handling has primarily always been "if you have to calculate something you store the result in a variable"). Adding this support has to be implemented on a keyword by keyword basis with individual implementations depending on accepted units and isn't trivial. I'll make a note of this but I don't know when we'll be able to get to it as we're trying to get more widely impacting web compatibility addressed first.
Can you please use css var() variables for the time being for compatibility?

[ron_1]

Has there been any update on this, or are we still in the lurch?

[Moonchild]

Has there been any update on this, or are we still in the lurch?

You know as much as anyone else. The entire communication is in this thread.

[ron_1]

You know as much as anyone else. The entire communication is in this thread.

That's what I was afraid of.