Reconcile with upstream changes

crates/ui2/src/elements/stack.rs

@@ -14,18 +14,18 @@ pub trait Stack: StyleHelpers {
     }
 }
 
-impl<S> Stack for Div<S> {}
+impl<S: 'static + Send + Sync> Stack for Div<S> {}
 
 /// Horizontally stacks elements.
 ///
 /// Sets `flex()`, `flex_row()`, `items_center()`
-pub fn h_stack<S: 'static>() -> Div<S> {
+pub fn h_stack<S: 'static + Send + Sync>() -> Div<S> {
     div().h_stack()
 }
 
 /// Vertically stacks elements.
 ///
 /// Sets `flex()`, `flex_col()`
-pub fn v_stack<S: 'static>() -> Div<S> {
+pub fn v_stack<S: 'static + Send + Sync>() -> Div<S> {
     div().v_stack()
 }