fix: clear hierarchy and dirty status in rebuild_layout to restore backplate dragging

 src/main.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main.rs b/src/main.rs
index e7ebbb6..20451b2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -496,6 +496,7 @@ impl ColorApp {
     }
 
     fn rebuild_layout(&mut self) {
+        self.ui_context.clear_hierarchy();
         let mut widgets = Vec::new();
         let mut text_items = Vec::new();
 
@@ -625,6 +626,7 @@ impl ColorApp {
 
         self.widgets = widgets;
         self.text_items = text_items;
+        self.ui_context.clear_dirty();
         self.needs_rebuild = false;
     }
 }