Set padding after computing leftRightMargin

- Issue MatterHackers/MCCentral#2151
Investigate LibraryQueueViewRefreshesOnAddItem failure

Library/Widgets/ListView/IconListView.cs

@@ -91,9 +91,6 @@ namespace MatterHackers.MatterControl.CustomWidgets
 					}
 				}
 
-				// put in padding to get the "other" side of the outside icons
-				this.Padding = new BorderDouble(leftRightMargin, 0);
-
 				reflowingContent = false;
 			}
 
@@ -127,6 +124,9 @@ namespace MatterHackers.MatterControl.CustomWidgets
 			// set the margin to be 1/2 the space (it will happen on each side of each icon)
 			leftRightMargin = (int)(remainingSpace > 0 ? spacePerColumn / 2 : 0);
 
+			// put in padding to get the "other" side of the outside icons
+			this.Padding = new BorderDouble(leftRightMargin, 0);
+
 			return newColumnCount;
 		}