Add back the changes from #250ffff

Author: mytdragon

src/widget/drop_down.rs

@@ -296,6 +296,48 @@ where
             )
             .height(*self.height);
 
+        let limits = {
+            let max = limits.max();
+
+            // Offset is computed from the reference rect, it isn't a translation vector.
+            let width_before = self.underlay_bounds.x - self.offset.x;
+            let width_after =
+                max.width - self.underlay_bounds.x - self.underlay_bounds.width - self.offset.x;
+            let height_above = self.underlay_bounds.y - self.offset.y;
+            let height_below =
+                max.height - self.underlay_bounds.y - self.underlay_bounds.height - self.offset.y;
+
+            let ref_center = self.underlay_bounds.center();
+            let max_width_symmetric = ref_center.x.min(max.width - ref_center.x) * 2.0;
+            let max_height_symmetric = ref_center.y.min(max.height - ref_center.y) * 2.0;
+            match self.alignment {
+                Alignment::TopStart => limits
+                    .max_height(height_above + self.underlay_bounds.height)
+                    .max_width(width_before),
+                Alignment::Top => limits
+                    .max_height(height_above)
+                    .max_width(max_width_symmetric),
+                Alignment::TopEnd => limits
+                    .max_height(height_above + self.underlay_bounds.height)
+                    .max_width(width_after),
+                Alignment::End => limits
+                    .max_width(width_after)
+                    .max_height(max_height_symmetric),
+                Alignment::BottomEnd => limits
+                    .max_height(height_below + self.underlay_bounds.height)
+                    .max_width(width_after),
+                Alignment::Bottom => limits
+                    .max_height(height_below)
+                    .max_width(max_width_symmetric),
+                Alignment::BottomStart => limits
+                    .max_height(height_below + self.underlay_bounds.height)
+                    .max_width(width_before),
+                Alignment::Start => limits
+                    .max_width(width_before)
+                    .max_height(max_height_symmetric),
+            }
+        };
+
         let mut node = self
             .element
             .as_widget()