1702861 - Firefox window doesn't fit whole screen in Tablet mode

Status: UNCONFIRMED

(Core :: Widget: Win32, defect, P3)

Description

[Fan]

Attachment: firefox_bug.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:87.0) Gecko/20100101 Firefox/87.0

Steps to reproduce:

1. Enable Windows 10 Tablet mode (Settings > System > Tablet > Change additional tablet settings)
2. Make sure “docked” option is selected in Windows 10 touch keyboard settings
3. Open Firefox
4. Open touch keyboard
5. Close Firefox
6. Reopen Firefox > empty space at the bottom

The bug can also be reproduced when splitting screen (horizontally or vertically).

Actual results:

Firefox does not fit whole screen at launch.
It is an annoying bug that exists for a long time (several years).

Expected results:

In Tablet mode, apps are supposed to start maximized.

Comment 1

[Fan]

Also reported here: https://www.reddit.com/r/Surface/comments/a55kyh/firefox_doesnt_open_maximized_full_screen_in/

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Win32' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 3

[Yannis Juglaret [:yannis]]

Hello! Thank you for reporting this bug, although this was some time ago now. Can you please clarify the following:

• Do you still have the problem today with an up-to-date version of Firefox?
• Do you experience this bug on an actual tablet, or on a PC with Windows 10 in Tablet mode?

I tried to reproduce this on a PC with Windows 10 after switching to Tablet Mode, what I noticed was that the window would initially use the size from the last use of Firefox in Desktop mode if starting Firefox from the Tablet mode's list of apps. Bringing the keyboard then removing it would make Firefox become full-screen again. But I didn't manage to reproduce the big black row at the bottom we can see in the screenshot. So I'm not sure if it's the same problem.

Comment 4

[Fan]

Hello!

(In reply to Yannis Juglaret from comment #3)

Hello! Thank you for reporting this bug, although this was some time ago now. Can you please clarify the following:

• Do you still have the problem today with an up-to-date version of Firefox?

Yes, I do. FF 106.0.1 on W10 22H2.

• Do you experience this bug on an actual tablet, or on a PC with Windows 10 in Tablet mode?

It's a PC in Tablet mode.

I tried to reproduce this on a PC with Windows 10 after switching to Tablet Mode, what I noticed was that the window would initially use the size from the last use of Firefox in Desktop mode if starting Firefox from the Tablet mode's list of apps. Bringing the keyboard then removing it would make Firefox become full-screen again. But I didn't manage to reproduce the big black row at the bottom we can see in the screenshot. So I'm not sure if it's the same problem.

Additionnal requirement to reproduce: You have to enable "Restore previous session" option on startup.

Comment 5

[Fan]

Attachment: FF-Touch-keyboard.gif