curves are locked in some axises and can not be edited
 

hello
I have this bad problem about creating and editing curves...
sometimes when I create a curve in one of the views other than perspective, the curve appears to be locked in one of the 3 axises. means for example I can not move the curve point in Y axis or X.
why this happens?
can I do something about this?

thanks alot

check the channel layer. if some translation axis is greyed out - rightclick and unlock.