Keyboard mapping characters with both shift keys

[Ankitkumar Rameshchandra Patel]

What's the expected results of Left_Shift + Right_Shift + Any Key?

I have tried Left_Shift + Right_Shift + each individual key combination 
of QWERTY keyboard in text editor (e.g. gedit) and got the following 
results:

~!@#$%^&*()_+
QWERUIOP|
ASDFGHJKL:"
BN?

If you notice, there are many English alphabets not being displayed. 
e.g. Left_Shift + Right_Shift + t = <nothing> , same for y, z, x, c, v 
and m keys.

Is this a correct behavior?

-- 
Ankit Patel