Affected versions

• 81.0a1 (20200816214203)

Affected platforms

• Ubuntu 18.04
• macOS 10.15.6
• Windows 10x64
• Windows 10aarch64

Steps to reproduce

1. Launch FF.
2. Open any webpage and trigger the new Print UI modal.
3. Close the modal.

Expected result

• New printing modal is correctly opened and closed.

Actual result

• There is a glitch when the new modal is opened/closed. A resize/shrink can be spotted (see attached).

Suggested Severity

• I'd suggest marking this as an S3 since it's only seen for a fraction of a second and it does not affect the functionality.

Regression range
This seems to be a recent regression.

• Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=626c0384ddb82f690f173af5730a5e07b0d28f53&tochange=b1d9164521d9ab722167399bfdda3b3c6753ce62

(In reply to Cornel Ionce [:cornel_ionce], Desktop Release QA from comment #0)

• There is a glitch when the new modal is opened/closed. A resize/shrink can be spotted (see attached).

By "glitch", do you mean that it starts wider, but then is resized to be narrower? Also, you say "opened/closed", but this only happens on opening unless I misunderstand.

(In reply to Jonathan Watt [:jwatt] from comment #1)

By "glitch", do you mean that it starts wider, but then is resized to be narrower? Also, you say "opened/closed", but this only happens on opening unless I misunderstand.

Yes. It starts wider and the it's resized. It happens each time when the preview is opened but I have also seen it happening when closing the UI, intermittently.

(Randomly picking P1, since we've already got a patch. 😉)

Closing this out because Mark's patch in bug 1653317 fixed this issue

Confirming this is fixed across platforms using latest 81 Nightly, build ID 20200820212107.