Hey, Bloom here. I currently am running Forge 1.7.10 along with bkspkrs core and the three main HUDs, alongside MapWriter and your Physics mod :P I am currently unable to drop an item that is in my hotbar unless I physically open my inventory and hover over the item and drop it, as shown in this gyazo:

http://gyazo.com/7a2066a66a3c5e45a3027f17746ac3f6.mp4

I have my drop button set to "V" and even after changing all commands to default, it worked to no avail. I hope to hear from you soon to see what may be causing this! :o

That shouldn't happen i will try to solve this problem.

Thank you very much

Hm, i tested it and i could change my key for dropping to 'v'. I have no idea why it shouldn't work :(