I need to have panel behavior in chrome: something always on top but that does not impair the navigation (in any other way than masking a few pixels).
We have two op
I found how GTalk is the only extension with panels. You can have panels too in your own extension, using really dark magic:
In your manifest.json, add the key-value pair:
"key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDsDApubb73tPfYlNIFxDu3K3/EHgV6/YOJXJkld1OZ20jW/cOht1j0NggnXhQYuu1mXFUufud4I2N7b5ydyg09gcM9Va3Zk17RhNV9smbPHOd4XlzJeXifX/9MgHPu4FzCen3CiSXsOeAELJIXEuT28xICriuUko/rNPwGeIB9VwIDAQAB"
And BOOM, panels activated!
This is Google's way of activating a hidden feature. The documentation tells us "key"'s purpose is to provide a unique identifier but that we don't really need it. As demonstrated, it also activates hidden features.
Also, you cannot have two extensions with the same "key" value (GTalk gets uninstalled). And I think your extension might not make it to the chrome store.
If you know someone at Google, please tell them we mortals would really really love to have panels too. Panels are awesome. And they are the only way to display information on top of a web page while still interacting with it. Google should share the love, we really need panels.