Mouse pointer stuck but computer completely functional

As I am writing this question, my Ubuntu 18.04 has again hit the problem that it often hits:

1. it is completely functional. I can open and close applications with a breeze through my keyboard.
2. I can move the mouse pointer around.
3. The mouse pointer icon is stuck, and clicking the mouse pointer anywhere does not do any interaction it at all. For example, clicking on the Chrome icon won't launch it, won't in fact do anything, however, launching it via the keyboard works. The same applies to any mouse clicks, they don't simply occur, as if nothing was clicked.

I checked the memory usage via top and it doesn't seem to be very high in total (<50%). What's the problem and how to fix it?

List of the gnome extensions I am using:

drwxrwxr-x 5 gt gt 4096 Dec 17 17:22
drwxrwxr-x 7 gt gt 4096 Dec 17 17:25
drwxrwxr-x 5 gt gt 4096 Dec 17 17:29
drwxrwxr-x 2 gt gt 4096 Dec 17 17:29 

Output of free -h (not at the time my mouse pointer was stuck):

 total used free shared buff/cache available
Mem: 3.3G 1.8G 255M 70M 1.3G 1.3G
Swap: 2.0G 0B 2.0G

sudo lshw -C memory:

*-firmware description: BIOS vendor: Insyde physical id: 0 version: F.10 date: 07/25/2016 size: 128KiB capacity: 8128KiB capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb uefi *-cache:0 description: L1 cache physical id: 5 slot: L1 Cache size: 256KiB capacity: 256KiB clock: 1GHz (1.0ns) capabilities: pipeline-burst internal write-back unified configuration: level=1 *-cache:1 description: L2 cache physical id: 6 slot: L2 Cache size: 2MiB capacity: 2MiB clock: 1GHz (1.0ns) capabilities: pipeline-burst internal write-back unified configuration: level=2 *-memory description: System Memory physical id: 1d slot: System board or motherboard size: 4GiB *-bank:0 description: SODIMM DDR3 Synchronous Unbuffered (Unregistered) 1600 MHz (0.6 ns) product: HMT451S6DFR8A-PB vendor: Hynix physical id: 0 serial: 065580E3 slot: Bottom-Slot 1(Left) size: 4GiB width: 64 bits clock: 1600MHz (0.6ns) *-bank:1 description: SODIMMProject-Id-Version: lshwReport-Msgid-Bugs-To: FULL NAME <EMAIL@ADDRESS>PO-Revision-Date: 2012-02-05 00:26+0000Last-Translator: Andi Chandler <Unknown>Language-Team: English (United Kingdom) <>MIME-Version: 1.0Content-Type: text/plain; charset=UTF-8Content-Transfer-Encoding: 8bitX-Launchpad-Export-Date: 2018-07-12 13:19+0000X-Generator: Launchpad (build 18719) [empty] product: Empty vendor: Empty physical id: 1 serial: Empty slot: Bottom-Slot 2(Right)

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.