Hi,
After the update (1.4.3 to 1.4.6) when i try to create an invoice or a quote i can only see my first client the drop down will not work so i can’t select any other client.
I do have the same issue with the 1.5.5 version.
For me It was an issue with the cache.
Try 2-3 “hard refresh” (Ctrl + F5) or clean you browser cache, it should work a bit later.