The bug
Blocks cannot be placed on fences with the off-hand.
How to reproduce
Hold torch in offhand
Right click on top of a fence
You can't place it
Code analysis
The method net.minecraft.block.BlockFence.onBlockActivated(World worldIn, BlockPos pos, IBlockState state, EntityPlayer playerIn, EnumHand hand, EnumFacing facing, float hitX, float hitY, float hitZ) returns true if your mainhand is empty or holding a lead. This is also the reason for MC-21433. Since the method returns true when there's nothing in your mainhand, the offhand is ignored.
Linked issues
is duplicated by 11
MC-85571
torches can not be put on fences using the hotkey f
Resolved
MC-86447
Offhand place doesn't work on fence
Resolved
MC-86764
Bugs Fence + torche
Resolved
MC-94047
UNABLE TO PLACE TORCH ON A FENCE WITH THE LEFT HAND
Resolved
MC-96075
Carpets can't be put on fences when the carpet is in offhand
Resolved
relates to 5
MC-4582
Can't eat, throw, or shoot while looking at an Iron Door/Iron Trapdoor
Resolved
MC-114718
Right clicking cake with empty main hand does not use item in off-hand
Open
MC-106826
Can interact with (eat) cake in creative mode/hunger bar is full
Resolved
MC-93651
No placement sound when placing blocks on fence
Resolved
MC-298197
Attaching a lead to a fence also places the block in the off-hand slot
Reopened
Attachments
Comments 55
Confirmed for
16w15b
When you hold SHIFT you are able to place the block, however for the mainhand this is not the case, see MC-93651
Same reason as for MC-93651
The client thinks it interacted with its mainhand with the fence, and because of this does not try to use the offhand.
Likely caused by fences having a right click action (for leashes).