Add 'Has' to layout flags

layout_flags.go

@@ -75,6 +75,7 @@ const (
 	LFSizeAll = LayoutFlag(0x11110000)
 )
 
+func (f LayoutFlag) Has(fl LayoutFlag) bool { return f&fl != 0 }
 func (f LayoutFlag) Add(fl LayoutFlag)      { f |= fl }
 func (f LayoutFlag) Remove(fl LayoutFlag)   { f = f &^ fl }
 func (f LayoutFlag) ClearAll() {

wdgt_simple_list.go

@@ -228,7 +228,7 @@ func (w *SimpleList) MinW() int {
 func (w *SimpleList) MinH() int { return 4 }
 
 func (w *SimpleList) getItemAt(idx int) {
-	for idx >= len(w.List) {
+	for idx >= len(w.list) {
 		idx--
 	}