If you CTRL-Click a sign, it appears in your inventory with NBT+ data. Normally these items can be placed, retaining all their NBT data.
What I expected when I used this feature on a sign. The NBT+ sign would be placed with the text already filled in.
What actually happened; It opened the sign dialogue box once placed, as usual, for editing and disregarded the NBT data.
Duplicate of MC-48503