Override ui_context in Application impl for SystemInterface to enable backplate dragging

 src/main.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/main.rs b/src/main.rs
index a95f4f5..f0fd4e5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -411,6 +411,10 @@ impl cce_ui::engine::Application for SystemInterface {
         &self.text_items
     }
 
+    fn ui_context(&self) -> Option<&cce_ui::context::UiContext> {
+        Some(&self.ui_context)
+    }
+
     fn render_popovers(&self, pc: &mut dyn cce_ui::layout::RenderTarget) {
         cce_ui::layout::render_popovers(pc, &self.ui_context);