Alpha channel in viewport?

I tried to use a mapping with an alpha channel. How can I activate the alpha in the viewport? If I use the regular type “Game”-“Blender multitexture Materials” the alpha does not appear. If I change the display type to “Blender GLSL Materials” it works.
Is that normal? Nothing mentioned like this in the blender wiki

Thanks in advance

You can view it in the viewport only when the Texture Mode is active. You cannot view it in the Object or Edit mode or for that matter any other mode except for Texture Mode