panel: Apply a hard limit of 1/2 height

src/state.rs

@@ -241,6 +241,7 @@ impl Application {
     fn get_preferred_height(output: &OutputState) -> Option<u32> {
         output.get_pixel_size()
             .map(|px_size| {
+                let height = {
                     if px_size.width > px_size.height {
                         px_size.width / 5
                     } else {
@@ -251,6 +252,8 @@ impl Application {
                             px_size.width * 7 / 22
                         }
                     }
+                };
+                cmp::min(height, px_size.height / 2)
             })
     }