bugfix: free the shape-corners on the last used 'Shape'

the global 's_corners' vector was still used on an application shutdown
(including ctrl-c SIGINT). depending on when 's_corners' was created on
the stack this could lead to an exception ('pure virtual called') while
trying to free the 'FbPixmaps' without having a valid
'FbTk::Application::instance()' left.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/FbTk/Shape.cc b/src/FbTk/Shape.cc
index c0489ec..3d41886 100644
--- a/src/FbTk/Shape.cc
+++ b/src/FbTk/Shape.cc
@@ -134,7 +134,7 @@ void initCorners(FbWindow& win) {
 
 void cleanCorners() {
 
-    if (nr_shapes == 0) {
+    if (nr_shapes == 1) {
         s_corners.clear();
     } else {
         nr_shapes--; // refcounting