Tooltip: fix arrow separating from tooltip

src/utils/popper.js

@@ -932,7 +932,7 @@
         var sideValue = center - popper[side];
 
         // prevent arrow from being placed not contiguously to its popper
-        sideValue = Math.max(Math.min(popper[len] - arrowSize, sideValue), 0);
+        sideValue = Math.max(Math.min(popper[len] - arrowSize - 3, sideValue), 3);
         arrowStyle[side] = sideValue;
         arrowStyle[altSide] = ''; // make sure to remove any old style from the arrow