Ttgjyuk

To drag something with the mouse, it seems I have to hold the mouse button down for a fraction of a second before dragging (dragging immediately after clicking does not work).

I don't like this, but can't find any setting in the 'mouse & touchpad' settings to change it. Is there any way to reduce this delay?

I have the same problem, though it seems to come and go, depending on system updates from Canonical.

Interestingly, it was happening earlier to me until I plugged in an external USB mouse to test with. Now things are working perfectly, even when I remove the external USB mouse. By the way, my system is a Dell Vostro 2420 laptop with a trackpad.

And now it's back again, at least with the trackpad. External USB mouse works fine when I plug it in. It seemed to go bad after I did a two-finger click-drag to scroll with the trackpad.

The solution that's worked for me is toggling the input device on and off.

First you find the input device that's misbehaving:

foo@machine:$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ TPPS/2 IBM TrackPoint id=12 [slave pointer (2)]
⎜ ↳ SynPS/2 Synaptics TouchPad id=11 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
 ↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
 ↳ Power Button id=6 [slave keyboard (3)]
 ↳ Video Bus id=7 [slave keyboard (3)]
 ↳ Sleep Button id=8 [slave keyboard (3)]
 ↳ Integrated Camera id=9 [slave keyboard (3)]
 ↳ AT Translated Set 2 keyboard id=10 [slave keyboard (3)]
 ↳ ThinkPad Extra Buttons id=13 [slave keyboard (3)]

Then you toggle that ID on and off, for me it's always been the Synaptics TouchPad (ID=11):

foo@machine:$ xinput set-prop 11 "Device Enabled" 0
foo@machine:$ xinput set-prop 11 "Device Enabled" 1

And now its all working again, I think this is definitely a bug. I've randomly observed it across 3 different laptops, but haven't had the change to debug it.