This bug about swords. Swords don't dig in creative mode.

Hello Dear Sir & Madam,
First of all sorry about my bad English.
When i was playing Minecraft in creative mod i catched a bug.
I took a golden sword and i tried to dig dirt but unfortunately i didn't dig.
I tried all of them(iron,wooden,stone,diamond,golden) and all blocks include plants,glasses,rails e.g. then i failed. But i digged Minecrats(all types),boats and i extinguished fire. When i switch to survival mode i can dig all of them except bedrock. I recorded my test's little part and attached.
Respectfully,
Ziya ERKOC