With the XUL as XHTML patch test_copypaste.xul starts failing.

This is because for XUL documents we force plain text selection.

The above branch was added in bug 888839, because copy/paste of alert dialogs wasn't carrying formatting of newlines across. However, with current Firefox alerts, if I remove the above special branch, dialogs with newlines still work as expected.

Do you think we're fine to remove this special copy/paste behavior? If not, do you have an alternative way to keep the test passing in a post-XULDocument world?

Sorry, I'm late with this. Need to read also all of bug 723163

ok, and bug 888839 just added back something which bug 723163 removed.

The broader question is that how should copy-paste work in UI documents, when those are (X)HTML? Is that something we have considered? Or is it expected that all chrome (X)HTML is basically non-selectable, expect in special cases like alerts?

But still, XUL has had basically different copy-paste handling, so I guess that .xul test shouldn't be even loaded as xhtml.

(In reply to Olli Pettay [:smaug] from comment #3)

ok, and bug 888839 just added back something which bug 723163 removed.

The broader question is that how should copy-paste work in UI documents, when those are (X)HTML? Is that something we have considered? Or is it expected that all chrome (X)HTML is basically non-selectable, expect in special cases like alerts?

Copy/paste should largely behave the way it did with XUL documents. It's up to the element if the copy/paste is enabled/disabled. The above bug starts failing because the formatting changes in XHTML vs XUL.

I looked back at bug 723163, which is about about:crashes copy/paste formatting being messed up. However, if I apply my patch with force plain text selection disabled, the about:crashes text still copy/pastes as expected with newlines and spaces.

I still have yet to find anywhere in the UI that relies on newlines being preserved. If there are any places, it seems we could instead change it to be white-space:pre or something. Do you know of anywhere that needs the XUL behavior, or are we fine to remove it?

I don't know whether xul needs that behavior, especially these days.
But if we change behavior, better to test this a bit.

Could we change the check from !htmlorxhtml to chromedoc?

The force text plain formatting of copy/paste with XUL documents doesn't
appear to be needed anywhere anymore.

https://hg.mozilla.org/mozilla-central/rev/159e92b813b6