Disabling the flags

When we click on a flag and get to the translation page, the whole module should be replaced with a Back button to exit the Google and go back to the original language page.

That's rather hard to accomplish. See, GT is a proxy server that rewrites each URL in the html of the page it's showing you to also point to its proxy. It may be possible to work around this with some Javascript.

Having the flags there will create and issue when people will try to translate from already a translated page to another.

That should not be the case. The module does not display the block if the request is coming from GT's proxy. If you do get this behaviour you should file a bug report on that.

Also currently there is no option to go back to the original page or exit Google Translate.

Sadly, Google stopped displaying a button that would do that for you. Now you will need to open the links to GT in a new tab or window.

When we click on any flag, on the translated page that specific flag should disappear since we are already in that language mode.

The block should not display *at all* if the request is coming from GT. If you do get this behaviour you should file a bug report on that.

Closing, continuing in #602968: Block still visible in GT.