In this example,
Glossary entry "supplier" is found for source segment term "supplied" by dint of prefix matching.
Matchboard should show this result as
supplier + サプライヤー (in original form)
supplied + サプライヤー (source segment term + found translation)
Whether finding matches by dint of prefix matching or stem look-up, Matchboard should not show term/phrase pairs that do not exist in any resources; otherwise, it causes lots of confusion.
"Confusion" leads to additional, unnecessary work.
Upon seeing this kind of pair (e.g., supplied + サプライヤー) on Matchboard, which is obviously wrong, I'd be prompted to check if my resource is okay or not. Until I do so, I don't know exactly how prefix matching or stem look-up has worked.
Hence, confusion and unnecessary work.
Yes, that might be a preferable mode of display of the fuzzy results indeed. For the time being, please note that 'Prefix term' label in the Matchboard indicates that this may not be the exact matching of the source term.
If you launch a search in your TM(s), translate your segment and go to next one, CT stays on the search results tab (TM tab). So you have to click on the Matchboard tab each and every time after a search to keep translating with the Matchboard displayed... Or did I miss something?
Why don't you dock the Matchboard? Right click at its tab and choose a docking option. I recommend docking it to the main window vertically if you have a wide monitor.
You can always undock it by clicking at its icon at the bottom right-hand corner.