Ive read quite a few very similar issues on here as what follows, though none match the exact symptoms Im experiencing.
After a recent update, Ive noticed that when I minimize all my application windows, the unity desktop freezes for anything from 15 seconds to 3 minutes. I have two monitors, and while the mouse and keyboard both work perfectly fine, I cant move the mouse cursor off of the monitor screen its on when this freeze begins. Clicking on anything does nothing (at least, not for a long time), and I can do things like hit "Ctrl Alt Del" to bring the logout modal up. Clicking on icons in the unity launcher does nothing for this lockup time, and then after a large amount of time passes, all of the applications I clicked on suddenly open and everything runs as normal.
This isnt normal lag, as in the system performing slow or sluggish. Its just the unity desktop becomes unresponsive for minutes at a time exactly when I minimize the last application that isnt minimized. As long as I dont minimize windows, everything seems to run fine. Immediately after booting up, its also running fine. As soon as I open a single application and then minimize the window, the lockup/freeze begins.
Im on 14.04, and have been for a few months now, and just started experiencing this issue in the last week or so. The machine its on has a 500GB SSD drive, quad core 3.2ghz, 16GB ram, and a decent nVidia display card with recent proprietary drivers. I am away from that machine currently, and can post full specs later. I am taking a wild guess that this is related to a recent update, and some conflict between the unity desktop and nvidia display drivers.
Anyone else experiencing this, and know how to resolve?
Its a bug that occurs with desktop icon viewability set to off (can be enabled/disabled with a tool like ubuntu tweak). After a recent system update, if you change this setting to hide desktop icons from view in the desktop, you might get this lockup-on-minimize behavior.
Case closed, Ill report this on launchpad.