Try to put a chest in your off-hand, Then try putting it over another chest. To do that you need to press shift, But even if you shift your off hand will not be effected.
MC-84224
Shift does not work with the off-hand slot
Resolved
Fixed
1
(Unassigned)
Confirmed
Minecraft 15w31b, Minecraft 15w31c, Minecraft 15w32c
Minecraft 15w44b
Retrieved
This only works when the main hand is not holding anything.
Try doing this with a pickaxe or something without a right-click action in your main hand and the shift clicking works as expected.