Merge pull request #620 from charlestian23/puzzle_editor-short_truth_…

…table

Fixed the blank element to be categorized as a placeable element

src/main/java/edu/rpi/legup/puzzle/shorttruthtable/ShortTruthTableCell.java

@@ -152,7 +152,7 @@ public void setType(Element e, MouseEvent m) {
             }
             // Unknown Element
             else {
-                if (e.getElementID().equals("STTT-UNPL-0003")) {
+                if (e.getElementID().equals("STTT-PLAC-0003")) {
                     this.data = ShortTruthTableCellType.UNKNOWN;
                 }
                 // Argument Element

src/main/java/edu/rpi/legup/puzzle/shorttruthtable/elements/UnknownElement.java

@@ -1,9 +1,9 @@
 package edu.rpi.legup.puzzle.shorttruthtable.elements;
 
-import edu.rpi.legup.model.elements.NonPlaceableElement;
+import edu.rpi.legup.model.elements.PlaceableElement;
 
-public class UnknownElement extends NonPlaceableElement {
+public class UnknownElement extends PlaceableElement {
     public UnknownElement() {
-        super("STTT-UNPL-0003", "Unknown Element", "A blank tile", "edu/rpi/legup/images/shorttruthtable/tiles/UnknownTile.png");
+        super("STTT-PLAC-0003", "Unknown Element", "A blank tile", "edu/rpi/legup/images/shorttruthtable/tiles/UnknownTile.png");
     }
 }

src/main/java/edu/rpi/legup/puzzle/shorttruthtable/elements/shorttruthtable_elements_reference_sheet

@@ -1,6 +1,6 @@
 STTT-UNPL-0001 : ArgumentElement
 STTT-UNPL-0002 : ConditionalBiconditionalElement
-STTT-UNPL-0003 : UnknownElement
 
 STTT-PLAC-0001 : GreenElement
-STTT-PLAC-0002 : RedElement
+STTT-PLAC-0002 : RedElement
+STTT-PLAC-0003 : UnknownElement