On setting up a syntax search on a windows i7 2.4 Ghz machine (Logos 6 SR5) it took over two minutes for the pulldown of greek/transliterated words to appear.
for me (Windows), non-SBL edition never did populate - it just spins. On the SBL edition it is instantaneous (both on a fast computer).
Same here (Mac OS X 10.10) - it took about 90 seconds to populate (Logos 6 SR5).
Thank you. I have created a case to investigate this.
Improvements to this have been made in 6.1 (which should be in beta soon).
[Disclaimer: I am not advocating downloading the beta to solve your problem. All warnings about using the beta apply.]
6.1 is now available to all stable users.