Integer divide by zero when setting proportion of last flex item to 0

[fajuchem]

Hello, I'm using flex as the main window in the app, so what I need to do is hide some of the items of the flex, I archived it setting the the item proportion to 0 so the item became hidden, which works great, except when you try to set the proportion to 0 of the last item added in the flex.

package main

import "github.com/rivo/tview"

func main() {
	app := tview.NewApplication()

	test1 := tview.NewBox().SetBorder(true).SetTitle("test1")
	test2 := tview.NewBox().SetBorder(true).SetTitle("test2")
	test3 := tview.NewBox().SetBorder(true).SetTitle("test3")

	flex := tview.NewFlex().
		AddItem(test1, 0, 0, false).
		AddItem(test2, 0, 1, false).
		// Becase the last item is added with 0 its gonna panic
		// with integer division by zero
		AddItem(test3, 0, 0, false)

	if err := app.SetRoot(flex, true).Run(); err != nil {
		panic(err)
	}
}

Same thing happen if you try to resize the last item with:

    flex.ResizeItem(test3, 0, 0)

You gonna get:
panic: runtime error: integer divide by zero [recovered] panic: runtime error: integer divide by zero

[rivo]

Thanks. I added a fix. But I should note that the documentation does not allow this:

The proportion must be at least 1 if fixedSize == 0 (ignored otherwise).