Modified the default label text box into a drop down (#824)

* Modified the default label text box into a drop down

* Unchecked the box at startup

* Removed commented code

* Removed unnecessary update method for the combobox

* Changed naming style for class

libs/default_label_combobox.py

@@ -0,0 +1,27 @@
+import sys
+try:
+    from PyQt5.QtWidgets import QWidget, QHBoxLayout, QComboBox
+except ImportError:
+    # needed for py3+qt4
+    # Ref:
+    # http://pyqt.sourceforge.net/Docs/PyQt4/incompatible_apis.html
+    # http://stackoverflow.com/questions/21217399/pyqt4-qtcore-qvariant-object-instead-of-a-string
+    if sys.version_info.major >= 3:
+        import sip
+        sip.setapi('QVariant', 2)
+    from PyQt4.QtGui import QWidget, QHBoxLayout, QComboBox
+
+
+class DefaultLabelComboBox(QWidget):
+    def __init__(self, parent=None, items=[]):
+        super(DefaultLabelComboBox, self).__init__(parent)
+
+        layout = QHBoxLayout()
+        self.cb = QComboBox()
+        self.items = items
+        self.cb.addItems(self.items)
+
+        self.cb.currentIndexChanged.connect(parent.default_label_combo_selection_changed)
+
+        layout.addWidget(self.cb)
+        self.setLayout(layout)