Bug 513711

SUMMARY
When tagging people in the preview view, each time I confirm a name, after something like 500ms to 1sec, the UI hangs preventing from confirming the next face. It then seems like it is reloading, hangs again, reloads again and finally, after like 2-5 seconds, I'm able to confirm the next face. Wouldn'T there be a way to keep the UI free and do the work in the background? Maybe wait for the image to change to another one before saving to file?

STEPS TO REPRODUCE
1. Open a picture with multiple unconfirmed face tags
2. Confirm face #1
3. Immediately try to confirm face #2

OBSERVED RESULT
The UI hangs multiple times, the regions are reloaded multiple times, preventing the flow

EXPECTED RESULT
The UI to stay responsive during all the process and no flickering of the regions

SOFTWARE/OS VERSIONS
digiKam: 8.8.0
KDE Frameworks: 6.17.0
Qt: Using 6.9.1 and built against 6.9.1
Windows 11 Version 25H2
Build ABI: x86_64-little_endian-llp64
Kernel: winnt 10.0.26200 

ADDITIONAL INFORMATION
My DB is local is SQLLite on a local 
My pictures are stored on a 7-bay Synology NAS with 1Gbps interface delivering a measure stable 100+MiB/sec
The PC is a Ryzen9 6900HX with Radeon (8 cores / 16 threads) with 32GiB/RAM
The only work going on the machine at that point was DigiKam.