[Bug Report] Tabs slider not showing or showing misaligned

[mrodal]

Environment

Vuetify Version: 2.2.23
Vue Version: 2.6.11
Browsers: Chrome 81.0.4044.92
OS: Windows 10

Steps to reproduce

There are 2 cases:

Case 1:

1. have a v-tabs next to something that changes the tabs position
2. make the something move the tabs

Case 2:

1. Have a tabs initially hidden
2. Show the tabs

Expected Behavior

Case 1:
The slider adjustes its position accordingly

Case 2:
The slider appears with the tabs in the correct position

Actual Behavior

Case 1:
The slider adjusts its position wrong

Case 2:
The slider doesnt appear

Reproduction Link

https://codepen.io/mrodal/pen/jObyJbe

[jacekkarczmarczyk]

Duplicate of #4733 and others https://github.com/vuetifyjs/vuetify/issues?q=is%3Aissue+callSlider+is%3Aclosed

[mrodal]

@jacekkarczmarczyk on #4733 @KaelWD says

We may add some sort of resize observer eventually

Isn't v-mutate just that? Cant that be used?

[jacekkarczmarczyk]

Maybe in some cases it would work, but there's for example issue when the font file is loaded and font size is changed - in this case it don't think mutation observer would be triggered