Resizing VDI with VBoxManage, shows incorrect value in the Details pane and/or MediaManager

[Socratis]

Summary
Resizing a dynamic VDI (no snapshots) from the CLI, does not reflect the new size in the Details pane and/or the MediaManager.

Setup

• Host: OSX 10.9.5, 10.11.6, 10.13.6
• !VirtualBox: 5.2.0, 5.2.27, 6.0.5 and 6.0.97, didn't try even earlier, they're EOLed.
• Guest: a Win7-32 and a FreeDOS VM, doesn't really matter.
• VDI size: 80 GB and 500 MB respectively.

Example with the Win7 / 80 GB VDI:

$ VBoxManage showmediuminfo /Users/Shared/VirtualBox/Machines/Win/Win.vdi 
UUID:           6b59350c-5ca0-4265-9920-0805864801dd
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       /Users/Shared/VirtualBox/Machines/Win/Win.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       81920 MBytes
Size on disk:   14473 MBytes
Encryption:     disabled
In use by VMs:  Win (UUID: 54c42cec-1890-4ec1-ae7a-aacb7677e6db)

$ VBoxManage modifymedium /Users/Shared/VirtualBox/Machines/Win/Win.vdi --resize 102400
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

$ VBoxManage showmediuminfo /Users/Shared/VirtualBox/Machines/Win/Win.vdi 
...
Capacity:       102400 MBytes     <-- That's correct!
...

The problem is that in the Details of the VirtualBox Manager the newly 100 GB ($NEW_SIZE) is not reflected. It still shows the VDI as being 80 GB ($OLD_SIZE).

Using the latest test/development builds at the writing of the ticket, 2019-03-01:

• 5.2.0 r118431, 5.2.27 r129042
  Not even the MediaManager shows the correct size, it shows 80 GB. Only a complete restart of VirtualBox correctly identifies the VDI as being 100 GB on both the Details pane and the MediaManager.

• 6.0.5 r129045, 6.0.97 r129043
  Just opening MediaManager "forces" the Details pane to be updated to 100 GB, otherwise it's still identified as 80 GB in the Details.

[Socratis]

I know it's not "supported", but that's the best I can offer at the moment, I'm in a ... transitioning phase right now:

• Host: Win7-32 (6.1.7601: SP1)
• !VirtualBox: 6.0.2 r128162
• Guest: FreeDOS 1.2

Same behavior as the 6.0.x series, a trip to the MediaMager is required to update the value shown in the Details pane.