Dragging tabs around can cause empty regions

[Martmists-GH]

Code:

class MainApplication : Application() {
    override fun start(stage: Stage) {
        val root = DetachableTabPane()
        val scene = Scene(root)

        (0..3).forEach {
            root.tabs.add(DetachableTab("Tab $it").apply {
                content = Text("Content $it")
            })
        }

        stage.scene = scene
        stage.show()
    }
}

After playing around with it a bit, the application somehow ended up like this:

[Martmists-GH]

After experimenting for a bit, it seems to be caused by moving the topmost/leftmost tab of a row/column.

[jingglang]

Please try to set the DetachableTabPane.setCloseIfEmpty(true).