Launcher Right-Click Menu Gets Stuck and Renders Screen Unresponsive - 18.04

Sometimes launcher right-click menu of, for instance, Files gets stuck on screen and eventually causes Gnome UI to become totally unresponsive.

When I right-click and don't select a menu item and click elsewhere, right-click menu gets stuck on screen, and overlays any other active window. Or else I select a menu item of it, then whole screen items become unresponsive except cursor. After that, when I lock and unlock the current user session, then stuck menu disappears and screen becomes responsive.

I encounter this problem more frequent than occasionally.

System Info:

Dell Inspiron 3543
Ubuntu 18.04 LTS
Memory: 7.7 GiB
Processor: Intel® Core™ i7-5500U CPU @ 2.40GHz × 4 
Graphics: GeForce 840M/PCIe/SSE2
Gnome: 3.28.2
OS type: 64-bit

Graphics Driver:

sudo lshw -c video
*-display
   description: 3D controller
   product: GM108M [GeForce 840M]
   vendor: NVIDIA Corporation
   physical id: 0
   bus info: pci@0000:08:00.0
   version: a2
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress bus_master cap_list rom
   configuration: driver=nvidia latency=0
   resources: irq:52 memory:f6000000-f6ffffff memory:e0000000-efffffff memory:f0000000-f1ffffff ioport:d000(size=128) memory:f7000000-f707ffff

Solution 1:

Reloading works for me: Alt+F2, r, enter

Solution 2:

I have this same experience. When I right click (for example) the firefox icon on the launcher to open a new window, it sometimes causes the popup menu to freeze and my mouse is unable to click on anything.

I reset it using the following...

• First, I have to Alt-Tab away to allow my mouse clicks to function.
• Then I click on the applications icon at the bottom left.
• Then click the applications icon again to return to desktop.

This seems to reset the launcher.