Fixed disappearing scrollbars

Scrollbar visibility depends on it having a non-zero area.

2 files changed, 9 insertions, 3 deletions

diff --git a/src/ui/listwidget.c b/src/ui/listwidget.c
index a43b11ee..f7c43a93 100644
--- a/src/ui/listwidget.c
+++ b/src/ui/listwidget.c
@@ -148,11 +148,16 @@ void updateVisible_ListWidget(iListWidget *d) {
     const int   contentSize = size_PtrArray(&d->items) * d->itemHeight;
     const iRect bounds      = innerBounds_Widget(as_Widget(d));
     const iBool wasVisible  = isVisible_Widget(d->scroll);
-    if (area_Rect(bounds) == 0) {
+    if (width_Rect(bounds) <= 0 || height_Rect(bounds) <= 0) {
         return;
     }
+    /* The scroll widget's visibility depends on it having a valid non-zero size.
+       However, this may be called during arrangement (sizeChanged_ListWidget_),
+       which means the child hasn't been arranged yet. The child cannot update
+       its visibility unless it knows its correct size. */
+    arrange_Widget(as_Widget(d->scroll));
     setMax_SmoothScroll(&d->scrollY, scrollMax_ListWidget_(d));
-    setRange_ScrollWidget(d->scroll, (iRangei){ 0, d->scrollY.max });
+    setRange_ScrollWidget(d->scroll, (iRangei){ 0, d->scrollY.max });    
     setThumb_ScrollWidget(d->scroll,
                           pos_SmoothScroll(&d->scrollY),
                           contentSize > 0 ? height_Rect(bounds_Widget(as_Widget(d->scroll))) *
diff --git a/src/ui/scrollwidget.c b/src/ui/scrollwidget.c
index ff5144b2..0bab601a 100644
--- a/src/ui/scrollwidget.c
+++ b/src/ui/scrollwidget.c
@@ -54,7 +54,8 @@ struct Impl_ScrollWidget {
 };
 
 static void updateMetrics_ScrollWidget_(iScrollWidget *d) {
-    as_Widget(d)->rect.size.x = gap_UI * 3;
+    iWidget *w = as_Widget(d);
+    w->rect.size.x = gap_UI * 3;
 }
 
 static void animateOpacity_ScrollWidget_(void *ptr) {