Fix missing initialization of PreviewPlacerView

Bug: 8716050
Change-Id: I234f1134274b9f72c8abbd729783f9ffe8f20f64

java/src/com/android/inputmethod/keyboard/MainKeyboardView.java

@@ -1054,6 +1054,7 @@ public final class MainKeyboardView extends KeyboardView implements PointerTrack
 
     @Override
     public void onShowMoreKeysPanel(final MoreKeysPanel panel) {
+        locatePreviewPlacerView();
         if (isShowingMoreKeysPanel()) {
             onDismissMoreKeysPanel();
         }