Chat / Inventory Search losing characters

I occasionally need to answer emails, etc. and use the Command-Tab sequence to change to that app. When I return to Minecraft, I find that the c key and others seem to be ignored in the chat and the inventory search. In some cases, I can type 2-3 characters in the inventory search, the cursor backs up (apparently deleting anything that had been entered) and takes the last 2-3 characters entered.

Just noticed this with 1.8 and the upgrade to Yosemite. I've got the Java 1.6 JDK installed to support the Minecraft Launcher but I also have the Java 1.8_0_25 JDK installed to support some work I'm doing professionally. Lots of memory, nothing else loaded to interfere so I'm at something of a loss as to what is happening and why.

Thanks!