Another fixed bug introduced to clear_poly() in previous commit. Added process widget.

sandbox/process_widget.py

@@ -0,0 +1,20 @@
+import sys
+from PyQt4.QtGui import *
+
+app = QApplication(sys.argv)
+
+top = QWidget()
+halign = QHBoxLayout()
+top.setLayout(halign)
+busy_anim = QMovie("../share/busy16.gif")
+busy_anim.start()
+busy_anim_label = QLabel()
+busy_anim_label.setMovie(busy_anim)
+halign.addWidget(busy_anim_label)
+
+message_label = QLabel("Processing...")
+halign.addWidget(message_label)
+
+top.show()
+
+sys.exit(app.exec_())