Environment: Device: HTC Desire 820 (Android 6.0.1); Build: Nightly 55.0a1 (2017-04-04); Steps to reproduce: 1. Launch Fennec and have a tab or more open; 2. Launch Gmail and open a link via custom tabs; 3. Tap device recent apps button and bring Nightly from background; 4. Tap device recent apps button and bring Gmail from background; 5. Repeat step 3-4 and observe the tab increase and Expected result: Nightly and App using custom tab is loaded from background with no issues. Actual result: Nightly and App using custom tab have visual issues like increasing of tab drawer on Nightly and Notes: While testing this found that Bug 1352991 is reproducing here too. - Please check the video. - Tested with Chromer too.
Sorry, here is the video: https://youtu.be/jlqVMVBiOSE.
P2 per triage on april12