Android Question Grey line on edittext box


Licensed User
I try to make a form with few edittext, but when I try it on my device (LG G2 with stock ROM kitkat), some line appears on the edittext box.

I try to find solution on the forum, but don't find anything (or don't search enough)

Some picture:
Edittext.Enable = false

Edittext.Enable = on. The line are very transparent, but always here

I don't know what is the problem.

I develop under B4A v3.2.

Could you help me please ?
Sorry for bad english ...