Avoid a crash caused by a race conditon

 src/output.zig | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/output.zig b/src/output.zig
index 3106a74..bbe1a34 100644
--- a/src/output.zig
+++ b/src/output.zig
@@ -86,6 +86,11 @@ pub const Output = struct {
             output.root.current_focused_tags,
         );
         while (it.next()) |view| {
+            // This check prevents a race condition when a frame is requested
+            // between mapping of a view and the first configure being handled.
+            if (view.current_box.width == 0 or view.current_box.height == 0) {
+                continue;
+            }
             output.renderView(view, &now);
         }