+ WSJT-X does not provide any other way of conveying a "decoded callsign of interest" to another application. With the WSJT-X "Double click on call sets TX enable" option disabled, it takes only one mouse click on the WSJT-X Main window to click the "Enable TX" button if you're interested in working the station after seeing the DXKeeper lookup.
++ It's only 1 mouse click if there is only one call sign in the band activity window, but there are many double clicks plus the additional mouse click if there are many stations for which you are not sure if you worked them already or not. Tonight there are more than 50 stations decoded on 14.074 in FT8 in one time slot and more than 45 on 18.100 in FT8, just to give you an example. Therefore I still consider my assessment of "not convenient" is very valid.
On the other hand all decoded calls are listed as local spots more or less immediately in Spotcollector. Therefore I wonder if there is not any chance to look not only in the LotW- and eQSL-Member database but also in the log database and to have a certain color code in Spotcollector for those which are already in that database as worked.
As mentioned before: this is not any replacement of a contest logger such as N1MM or similar, it is just significantly improving the operating of FTx in WSJT-X (and this is different than working CW, SSB or RTTY in which I never felt the need of such a function outside of a contest and I am very happy in using DXLab a very long time already).
Anyway, thanks for looking into this topic.