System Information
Windows 7 Professional SP1 x64 (Japanese)
Core i7 3520M / Intel HD Graphics 4000

Blender Version
Broken: 2.69.0 r60995

Short description of error

Some keyboard inputs is dropping while running modal timer operator which handles 'TIMER' event and returns 'PASS_THROUGH'.

Especially, hitting same keys twice (quickly) and hitting another key, often cause dropping of latter key input.

This will happen even with 'Operator Modal Timer' template in text editor.

Exact steps for others to reproduce the error

1. open file
2. press 'Run Script' on text editor
3. try to input 'aabaabaabaabaabaab...' in python console
4. almost all 'b' will be skipped (you'll have 'aaaaaaaaaaaa...')