Steam opens multiple instances after todays update.

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.

Reproduce the behavior by closing Steam to the system tray and clicking its icon again to see whether a second instance opens. No file or test is identified in the issue; investigate the repository's Steam launch and tray integration, and consider the issue done when reopening restores the existing instance.

Written by the indexing model from the issue text.