VLAN management through "network connections"

[haleakalas]

I was trying to figure out an easy way to connect/disconnect to virtual lans from a workstation where I run Linux Min t 18.3. After checking all the utilities available through the GUI I noticed that "Network Connections" allowed me to create a VLAN entry into the list of interfaces available to use.
So, I created an entry for VLAN20 with the main ethernet interface as the parent and within seconds I could see and communicate with other machines using VLAN20 off of my main switch. That was amazingly easy.
But, I found odd the way things work with "Network Connections" or "Network Manager".
1) The vlan entry that I created, and which works as long as I check-mark'ed it as "automatic connection" doesn't appear in the list of interfaces in the system tray. So, there is no way to disconnect or reconnect at will using the GUI. For instance I can create 2 vlans; VLAN20 and VLAN30 and if they are set to connect automatically they get into a race condition. I have to edit them so that only one of them is in automatic mode to make it work. Ideally I would want none of them to be automatic so that using the GUI I can pick the interface that I want to use.
2) Once the vlan is created, even if it is not in use - because I didn't set it to connect automatically, the parent interface becomes unusable until such time I go destroy the vlan. This is not how it is supposed to work. A vlan definition, as long as it is not in use should not affect the parent interface - and it does not if instead of using the GUI based tool "Network Connection" I edit the file /etc/networking/interfaces...
Now my question are:
1) Am I using the wrong tool to setup a vlan through the GUI? Is there any other tools that I didn't figure out yet?
2) Is this behavior specific to Mint 18.3/Ubuntu 16.04 or is it also the same for Mint 19.1/Ubuntu 18.04?
Thanks for any insight/input/help.