Hope this helps:
OS Edition - Windows 11 Pro
Version - 25H2
OS Build - 26200.7840
Test Case 1 Configuration
Two Displays - configured as Extend these displays
Display #1 - configured as main display
Display #2 - configured as extension
Test Case 1 Scenarios:
Test 1:
Mp3Tag maximized on Display #1 (main display) - PASS - files are not removed from list view following tag maintenance
Test 2:
Mp3Tag maximized on Display #2 (extension) - FAIL - all files removed except for file that was clicked when exiting Tag Panel
Test 3:
Mp3Tag launched from Display #1 (main display), then extended over and shared with Display #2 (extension) - PASS
Test 4:
Mp3Tag launched from Display #2 (extension), then extended over and shared with Display #1 (main display) - FAIL
Test Case 2 Configuration
Two Displays - configured as Extend these displays
Display #2 - configured as main display
Display #1 - configured as extension
Test Case 2 Scenarios:
Test 1:
Mp3Tag maximized on Display #1 (extension) - FAIL - all files removed except for file that was clicked when exiting Tag Panel
Test 2:
Mp3Tag maximized on Display #2 (main display) - PASS - files are not removed from list view following tag maintenance
Test 3:
Mp3Tag launched from Display #1 (extension), then extended over and shared with Display #2 (main display) - FAIL
Test 4:
Mp3Tag launched from Display #2 (main display), then extended over and shared with Display #1 (extension) - PASS
Test Case 3 Configuration
Two Displays - configured as Duplicate these displays
Display #1 - configured as Duplicate
Display #2 - configured as Duplicate
Test Case 3 Scenarios:
Test 1:
Mp3Tag maximized on Display #1 (Duplicate) - PASS - all files removed except for file that was clicked when exiting Tag Panel
Test 2:
Mp3Tag maximized on Display #2 (Duplicate) - PASS - files are not removed from list view following tag maintenance
Test 3:
N/A
Test 4:
N/A
Important Note from my perspective: In all scenarios, tags are correctly applied to the selected items even when the list of files are removed.