SUMMARY
On Neon testing
If I have a stopped activity, it cannot be started again. Pressing on the activity icon in the "Activity Switcher" blinks the screen but otherwise does nothing, as well as using the D-Bus command `org.kde.ActivityManager /ActivityManager/Activities org.kde.ActivityManager.Activities.StartActivity {UUID}`

STEPS TO REPRODUCE
1. Have more than one activity
2. Open the activity switcher (META+Q by default) and press the "Stop Activity" button for one of the running activities
3. Open the activity switcher again (if it closed) and press on the activity name under "Stopped Activities"

OBSERVED RESULT
Nothing much happens

EXPECTED RESULT
The stopped activities should start and switch to

SOFTWARE/OS VERSIONS
Operating System: KDE neon Testing Edition
KDE Plasma Version: 6.2.80
KDE Frameworks Version: 6.7.0
Qt Version: 6.7.2
Kernel Version: 6.8.0-45-generic (64-bit)
Graphics Platform: Wayland
Processors: 20 × 12th Gen Intel® Core™ i7-12700H
Memory: 31.0 GiB of RAM
Graphics Processor: Mesa Intel® Graphics

ADDITIONAL INFORMATION
A workaround is to stop kactivitymanagerd, then edit its configuration file ~/.config/kactivitymanagerdrc and move all the stopped activity UUIDs from `stoppedActivities` to `runningActivities`, then start kactivitymanagerd again. If there are applications that are running on the stopped activity, they will not become accessible again.