Hierarchy is now responsible for focusing boxes when they are clicked

internal/system/box.go

@@ -336,13 +336,6 @@ func (this *box) handleMouseDown (button input.Button) (caught bool) {
 		this.invalidateStyle()
 	}
 	
-	if this.focusable {
-		this.SetFocused(true)
-	} else {
-		hierarchy := this.getHierarchy()
-		if hierarchy == nil { return }
-		hierarchy.focus(nil)
-	}
 	for _, listener := range this.on.buttonDown.Listeners() {
 		if listener(button) { caught = true }
 	}

internal/system/event.go

@@ -62,7 +62,16 @@ func (this *Hierarchy) HandleKeyUp (key input.Key, numberPad bool) {
 // information, HandleMouseMove must be called *before* HandleMouseDown.
 func (this *Hierarchy) HandleMouseDown (button input.Button) {
 	boxes := []anyBox { }
+	first := true
 	this.boxesUnder(this.mousePosition)(func (box anyBox) bool {
+		if first {
+			if box.canBeFocused() {
+				this.focus(box)
+			} else {
+				this.focus(nil)
+			}
+			first = false
+		}
 		boxes = append(boxes, box)
 		return !box.handleMouseDown(button)
 	})