Cannot move items in inventory

[jbminecraft7]

Title: Cannot move items in inventory

Version: 3.1.2

OS: Windows 7 64 Bit

Java Version: Java 7 (w/ Update from a few days ago)

Description of Problem:

While playing on my friend's tekkit server, I punched down some trees. When I tried to put them into my 2x2 crafting grid, I couldn't. When I tried to click on the logs, they did not drag around w/ my cursor, they just popped over to the top left slot of my inventory. Trying to click it from here, it popped over to my first hotbar space.

Error Messages:

N/A

Error Log:

N/A

[Backplague]

Your shift key is stuck.

[CoderJ]

did you alt-tab out of the client?

Sometimes the client will get confused and do this... try running full screen (F11) and see if that helps.