Always set the axis innermost property.

It doesn't make sense to calculate the innermost property only when no
tickLength has been provided; the two have little to do with each other.

examples/axes-multiple/index.html

@@ -32,7 +32,10 @@
 					position: position,
 					tickFormatter: euroFormatter
 				} ],
-				legend: { position: "sw" }
+				legend: { position: "sw" },
+				grid: {
+					borderWidth: { top: 0, bottom: 1, left: 0, right: 0}
+				}
 			});
 		}
 

jquery.flot.js

@@ -1395,13 +1395,15 @@ Licensed under the MIT license.
             if ($.inArray(axis, samePosition) == samePosition.length - 1)
                 axisMargin = 0; // outermost
 
-            // determine tick length - if we're innermost, we can use "full"
-            if (tickLength == null) {
-                var sameDirection = $.grep(all, function (a) {
+            // Determine whether the axis is the first (innermost) on its side
+
+            innermost = $.inArray(axis, $.grep(all, function (a) {
                 return a && a.reserveSpace;
-                });
+            })) == 0;
 
-                innermost = $.inArray(axis, sameDirection) == 0;
+            // determine tick length - if we're innermost, we can use "full"
+
+            if (tickLength == null) {
                 if (innermost)
                     tickLength = "full";
                 else