Dialog.Resize() has no effect if called before Dialog.Show()

[jens1205]

Describe the bug:

Dialog.Resize() only has an effect on the created dialog if it is called after Dialog.Show(). This is not consistent with window.Resize() which can be used before or after Show()

To Reproduce:

Screenshots:

Example code:

package main

import (
	"log"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/dialog"
	"fyne.io/fyne/v2/widget"
)

func main() {
	a := app.New()

	w := a.NewWindow("testwindow")

	button := widget.NewButton("dialog", func() {
		username := widget.NewEntry()
		password := widget.NewPasswordEntry()

		items := []*widget.FormItem{
			widget.NewFormItem("username", username),
			widget.NewFormItem("password", password),
		}

		form := dialog.NewForm("mydialog", "OK", "Cancel", items,
			func(ok bool) {
				if !ok {
					return
				}
				log.Println(username.Text, username.Password)
			}, w)

		// no effect
		form.Resize(fyne.NewSize(1000, 200))

		form.Show()

		// would work
		// form.Resize(fyne.NewSize(1000, 200))

	})

	w.SetContent(container.NewMax(button))

	// has an effect
	w.Resize(fyne.NewSize(1900, 1080))

	w.Show()

	// would also work
	// w.Resize(fyne.NewSize(1900, 1080))

	a.Run()

}

-->

Device (please complete the following information):

• OS: Linux
• Version: Ubuntu 20.04.1 LTS
• Go version: 1.15.7 linux/amd64
• Fyne version: v2.0.0

[AlbinoGeek]

Related to (but not a duplicate of): #1570 , #1565

Also possibly #1692 and #1382

[andydotxyz]

The fix for this is now on the develop branch