Meanwhile, I experimented with Logitech BT adapter and Logitech wireless mouse, by installing the Solaar daniel.pavel software. The Logitech mouse functioning was erratic. I then upgraded the software to the ppa version Solaar-unifying/stable for trials, and the performance worsened; so uninstalled the latter and reverted back to the former software. As I have still not found a solution to the frequently disconnecting Dell mouse on a Dell laptop, I am provisionally using Logitech mouse with Solaar daniel.pavel software. To my mind, appears to be a Blueman z issue, but unable to confirm. Any inputs on the issue?