Steam opens multiple instances after todays update.

[DekosAnjo]

Upon closing the window, it minimizes to the system tray. However, upon subsequent attempts to reopen it by clicking on the icon, rather than restoring the previous instance, a new one is launched.

[Arcitec]

This is not a new issue. It has existed for as long as Steam Flatpak has existed.

The Flatpak is simply bad at identifying the existing instance and reviving it. And it is probably a hard problem to solve since it's been here for years.

Duplicate issue: #1300

[Arcitec]

The four biggest issues with the Flatpak are as follows:

• It often opens multiple instances of Steam. Happens on both GNOME and KDE. Workaround: Don't close any Steam windows. Leave then open on another workspace. Then it will properly activate those windows.
• If you leave it open overnight, it loses connection to the NVIDIA driver and cannot launch any games until you fully exit the Steam Flatpak and start it again.
• SteamVR does not and will not work in Flatpak or Snap: https://help.steampowered.com/en/faqs/view/18A4-1E10-8A94-3DDA
• The Flatpak loses between 1-20% of the game FPS due to the sandbox filtering all kernel syscalls through a lengthy detour to ensure safety. This is a known issue with years of discussions to try to fix it.

That being said, I use the Steam Flatpak for a few reasons:

• The Flatpak makes it super easy to install tools such as gamemode, SteamTinkerLaunch etc, and keep them updated. It is very icky and painful to install those natively. Most distros don't package SteamTinkerLaunch, or do it seveeeeerely out of date.
• The Flatpak has a better system library environment. I have had issues with game anticheats failing on the native Steam and only working on the Flatpak.
• The Flatpak keeps all the Steam config files neatly contained in the sandbox instead of sprawling all over your home directory.
• It is safer in case a game contains a Windows or Linux virus. The Flatpak sandbox ensures that there is no mapping into the user's own system drive. With the native Steam, you could be infected or have files stolen by either native Linux games launched inside Steam, or by a Windows game containing malware. It is very rare, but it has happened in the past.

It is basically a case of "pick your poison". I prefer the Flatpak issues over the native issues. Most important for me is the extra sandboxing and the super easy installation of addon tools like SteamTinkerLaunch.

Certainly wish Valve made an official Flatpak though. But last time I saw any mention, their main concern was the worse game performance inside Flatpaks.