why the actived window is covered by other windows

[silentyears]

as subject，when i click on window A and drag it to the area where window B locates ，it's so strange that A is covered by B and A is actived meanwhile!
anybody knows any possibility?please tell me, thanks very much!

[Kulik]

I refuse to help you unless you finally read our guidelines and act by them! This is getting ridiculous, you have 29 posts, all of them of really really low quality.

btw: You already asked about this if I recall correctly. So just go over your past posts and you will find the answer.

When asking for help: Always post your CEGUI.log and the text of any error or exception messages. Thank you!

[silentyears]

I refuse to help you unless you finally read our guidelines and act by them! This is getting ridiculous, you have 29 posts, all of them of really really low quality.

btw: You already asked about this if I recall correctly. So just go over your past posts and you will find the answer.

When asking for help: Always post your CEGUI.log and the text of any error or exception messages. Thank you!

Thank you all the same!
I admit all posts are low quality, but it's difficult for me to update log and code, thanks for understanding , so i can only describe the question as possible as i can . I review the answer you tell me and it give me tip. And i find the result now, use "glenable(GL_LEQUAL)" before render.
thanks!!!