Thanks, that has greatly reduced the apparent CPU usage. I still see the process going active periodically, but the CPU usage when it goes active is only 0.1% now instead of the much high amount I reported before. I suspect that whatever polling loop you have active in the application runs into an error in the sandbox environment, and spends extra processing time dealing with the error. If you need any extra debug data, I can try reinstalling the App Store version and running any DTrace scripts you might have.

This is in regards to Dropzone 3 Version 3.2.3 (728)

Dropzone 3 seems to be consuming an inordinate amount of CPU time on my system when the application is primarily idle. The application seems to spike to large CPU usage every couple seconds (showing as anywhere from 13% - 56% cpu), and this is reflected in it's cumulative CPU time (larger than any other process on my system shown in Activity Monitor):

Dropzone 3      4:10:50.45
kernel_task      3:24:55.49
WindowServer  1:50:33.51
coreaudiod          45:18.17
sysmond             42:38.63

System uptime: 16:33  up 7 days,  3:30, 1 user, load averages: 1.34 1.24 1.29

System Specs:
MacBook Pro (late 2013 15" Retina)
OS X 10.10.2
2.3 GHz Intel Core i7
16GB 1600 MHz DDR3 Memory