Qt Frameless Applications are not behaving well

[keshavbhatt]

Description: Ubuntu Focal Fossa (development branch)
Release: 20.04

Bug Detail: Mutter behave differently with Qt Application with Frame-less flags.
 example: 1- they are not resizable.
          2- window snapping doesn't work.
          3- they cannot be moved around the screen like other apps.

Steps to reproduce:

1- Run any Qt frame-less window app (Qt::FrameLessWindowHint). (snap install olivia or snap install wonderwall, these are few apps which uses frame-less window hint optionally). You can build your own app with Qt if you have code.

2- Try to resize it.

3- Try to snap it to the edges.

4- Try to move it around the screen and try to move it long along X and Y axis.

Expected Behavior:

1- Qt::FrameLessWindowHint windows with Qt::Window/Widget/Dialog flag are supposed to be resized if they are not set to be remain FixSize.

2- Qt::FrameLessWindowHint windows with Qt::Window/Widget/Dialog are supposed to trigger snapping on window snapping gesture by user.

3- Qt::FrameLessWindowHint windows with Qt::Window/Widget/Dialog are supposed to move all the way along the X and Y axis of user's screen.

Note: Qt::FrameLessWindowHint enabled apps act normal under Unity7's Compiz/Metacity, KWin of KDE and xfwm of XFCE.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: mutter 3.36.1-3ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27
Uname: Linux 5.4.0-21-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.11-0ubuntu26
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon Apr 13 18:23:20 2020
InstallationDate: Installed on 2020-04-11 (2 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200329)
SourcePackage: mutter
UpgradeStatus: No upgrade log present (probably fresh install)

[keshavbhatt (keshavnrj)]

Video demonstrating the bug:

https://youtu.be/jw__11d4hEY

[Daniel van Vugt (vanvugt)]

I can't seem to find any existing reports of this problem. Please report it to the mutter developers at:

  https://gitlab.gnome.org/GNOME/mutter/-/issues

and then tell us the new issue ID.