Fix bug with re-showing old content

CHANGELOG.md

@@ -26,6 +26,8 @@ More detailed release notes can be found on the [releases page](https://github.c
 * Tab support for focus handling missing on mobile
 * ScrollToBottom not always scrolling all the way when items added to container.Scroller
 * Fixed scrollbar disappearing after changing content (#2303)
+* Calling SetContent a second time with the same content will not show
+
 
 ## 2.0.3 - 30 April 2021
 

internal/driver/glfw/window.go

@@ -475,6 +475,10 @@ func (w *window) SetContent(content fyne.CanvasObject) {
 	}
 
 	w.canvas.SetContent(content)
+	// show new canvas element
+	if content != nil {
+		content.Show()
+	}
 	w.RescaleContext()
 }
 

internal/driver/glfw/window_test.go

@@ -1148,6 +1148,20 @@ func TestWindow_CloseInterception(t *testing.T) {
 	assert.True(t, onClosed) // Close is called if the interceptor is not set.
 }
 
+func TestWindow_SetContent_Twice(t *testing.T) {
+	w := createWindow("Test").(*window)
+
+	e1 := widget.NewLabel("1")
+	e2 := widget.NewLabel("2")
+
+	w.SetContent(e1)
+	assert.True(t, e1.Visible())
+	w.SetContent(e2)
+	assert.True(t, e2.Visible())
+	w.SetContent(e1)
+	assert.True(t, e1.Visible())
+}
+
 // This test makes our developer screens flash, let's not run it regularly...
 //func TestWindow_Shortcut(t *testing.T) {
 //	w := createWindow("Test")