Use Formatter instead of regex in AbstractPopup.

src/main/java/edu/ntnu/stud/chaosgame/view/modificationpopups/AbstractPopup.java

 package edu.ntnu.stud.chaosgame.view.modificationpopups;
 
+import edu.ntnu.stud.chaosgame.controller.utility.Formatter;
 import javafx.geometry.Insets;
 import javafx.geometry.Pos;
 import javafx.scene.Scene;
@@ -13,6 +14,8 @@ import javafx.scene.layout.VBox;
 import javafx.stage.Modality;
 import javafx.stage.Stage;
 
+import java.text.Normalizer;
+
 /**
  * Abstract class for popups.
  */
@@ -129,13 +132,9 @@ public abstract class AbstractPopup {
    * @return the numeric text field.
    */
   protected TextField createNumericTextField() {
-    TextField textField = new TextField();
-    textField.textProperty().addListener((observable, oldValue, newValue) -> {
-      if (!newValue.matches("-?\\d*(\\.\\d*)?")) { // TODO: replace with Formatter
-        textField.setText(oldValue);
-      }
-    });
-    return textField;
+    TextField numberField = new TextField();
+    numberField.setTextFormatter(Formatter.getFloatFormatter());
+    return numberField;
   }
 
   /**

src/main/resources/descriptions/saved_descriptions/Heighway-Dragon.txt

-Affine2D
-Heighway-Dragon
--1.0, -1.0
-1.5, 1.5
-0.8, -0.3, 0.5, 0.5, 0.0, 0.0
--0.5, -0.5, 0.6, -0.6, 1.0, 0.0

src/main/resources/descriptions/saved_descriptions/Julia2.txt

-Julia
-Julia2
--1.6, -1.0
-1.6, 1.0
--0.8, 0.8