Prevent default when mousing down on a button that responds to clicks

This ensures that ancestors that track focus don't accidentally steal
it on mouse down, which was preventing the editor from deploying the
code actions menu.

crates/ui2/src/components/button/button_like.rs

@@ -1,4 +1,4 @@
-use gpui::{relative, DefiniteLength};
+use gpui::{relative, DefiniteLength, MouseButton};
 use gpui::{rems, transparent_black, AnyElement, AnyView, ClickEvent, Div, Hsla, Rems, Stateful};
 use smallvec::SmallVec;
 
@@ -372,10 +372,11 @@ impl RenderOnce for ButtonLike {
             .when_some(
                 self.on_click.filter(|_| !self.disabled),
                 |this, on_click| {
-                    this.on_click(move |event, cx| {
-                        cx.stop_propagation();
-                        (on_click)(event, cx)
-                    })
+                    this.on_mouse_down(MouseButton::Left, |_, cx| cx.prevent_default())
+                        .on_click(move |event, cx| {
+                            cx.stop_propagation();
+                            (on_click)(event, cx)
+                        })
                 },
             )
             .when_some(self.tooltip, |this, tooltip| {