@Nick: re: "(...) otherwise we will need to wait until the signal that the installation is in progress comes in before closing the dash".
I'm afraid it's not really doable with current framework; there is a su password popup after clicking 'Free download' and Dash needs to hide for it to show; on a side note, password popup is a system-wide solution triggered by apt and we've no control over it.
@Nick: re: "(...) otherwise we will need to wait until the signal that the installation is in progress comes in before closing the dash".
I'm afraid it's not really doable with current framework; there is a su password popup after clicking 'Free download' and Dash needs to hide for it to show; on a side note, password popup is a system-wide solution triggered by apt and we've no control over it.