SelectTab method does not in all cases correctly set the blue underline to the selected tab

[midu-SA]

Describe the bug:

Remove the last tabitem of a tab-container, then add a new tabitem and select it as the currently selected tab. The blue underline remains on the previous tabitem

To Reproduce:

Steps to reproduce the behaviour: run the example code

Example code:

package main

import (
"fyne.io/fyne/v2"
"fyne.io/fyne/v2/app"
"fyne.io/fyne/v2/widget"
"fyne.io/fyne/v2/layout"
"fyne.io/fyne/v2/container"
)

var del_button *widget.Button

func main() {
var container_tab *container.AppTabs
a := app.New()
w := a.NewWindow("container")

del_button = widget.NewButton ("delete", func() {
container_tab.Remove (container_tab.CurrentTab())
item := container.NewTabItem("Delete", make_delete_container() )
container_tab.Append(item)
container_tab.SelectTab (item)
})

container_tab = container.NewAppTabs(
container.NewTabItem("List", widget.NewButton ("list", func() {})),
container.NewTabItem("Delete", make_delete_container()),
)
container_tab.SelectTabIndex(0)
w.SetContent (container_tab)
w.ShowAndRun()
}

func make_delete_container () *fyne.Container {
return fyne.NewContainerWithLayout(layout.NewMaxLayout(), del_button)
}

Device (please complete the following information):

• OS: Linux
• **Version:**Debian 10
• Go version: 1.15.6
• Fyne version: 2.0

[AlbinoGeek]

Hey there!

Thank you for reporting this bug.

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[andydotxyz]

Fixed on develop branch for next v2.0.1 release