1/p bounds in ui

src/gui_qt/fit/fit_forms.py

@@ -86,15 +86,21 @@ class FitModelWidget(QtWidgets.QWidget, Ui_FitParameter):
             p = self.parameter_line.text().replace(',', '.')
 
         if self.checkBox.isChecked():
-            try:
-                lb = float(self.lineEdit.text().replace(',', '.'))
-            except ValueError:
-                lb = None
+            lb_text = self.lineEdit.text()
+            lb = None
+            if lb_text:
+                try:
+                    lb = float(lb_text.replace(',', '.'))
+                except ValueError:
+                    lb = lb_text
 
-            try:
-                rb = float(self.lineEdit_2.text().replace(',', '.'))
-            except ValueError:
-                rb = None
+            ub_text = self.lineEdit_2.text()
+            rb = None
+            if ub_text:
+                try:
+                    rb = float(ub_text.replace(',', '.'))
+                except ValueError:
+                    rb = ub_text
         else:
             lb = rb = None