fixed rearranging sound icons in the jukebox

gui.js

@@ -75,7 +75,7 @@ isRetinaSupported, SliderMorph, Animation, BoxMorph, MediaRecorder*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.gui = '2018-March-19';
+modules.gui = '2018-April-25';
 
 // Declarations
 
@@ -8393,7 +8393,7 @@ SoundIconMorph.prototype.renameSound = function () {
 
 SoundIconMorph.prototype.removeSound = function () {
     var jukebox = this.parentThatIsA(JukeboxMorph),
-        idx = this.parent.children.indexOf(this + 1);
+        idx = this.parent.children.indexOf(this) - 1;
     jukebox.removeSound(idx);
 };
 

history.txt

@@ -4086,3 +4086,7 @@ in development:
 180424
 ------
 * added 'name' selector to pixel library
+
+180425
+------
+* GUI: fixed rearranging sound icons in the jukebox