Simple map-tail minimalism. Fixes #467

js/id/modes/add_area.js

@@ -15,7 +15,7 @@ iD.modes.AddArea = function() {
             controller = mode.controller;
 
         map.dblclickEnable(false)
-            .tail('Click on the map to start drawing an area, like a park, lake, or building.');
+            .tail('Click on the map to start drawing an area, like a park, lake, or building.', true);
 
         function add() {
             var datum = d3.select(d3.event.target).datum() || {},

js/id/modes/add_line.js

@@ -16,7 +16,7 @@ iD.modes.AddLine = function() {
             controller = mode.controller;
 
         map.dblclickEnable(false)
-            .tail('Click on the map to start drawing an road, path, or route.');
+            .tail('Click on the map to start drawing an road, path, or route.', true);
 
         function add() {
             var datum = d3.select(d3.event.target).datum() || {},

js/id/modes/add_point.js

@@ -13,7 +13,7 @@ iD.modes.AddPoint = function() {
             history = mode.history,
             controller = mode.controller;
 
-        map.tail('Click on the map to add a point.');
+        map.tail('Click on the map to add a point.', true);
 
         function add() {
             var node = iD.Node({loc: map.mouseCoordinates()});

js/id/modes/draw_area.js

@@ -36,7 +36,7 @@ iD.modes.DrawArea = function(wayId) {
             .on('add', add);
 
         mode.map.surface.call(behavior);
-        mode.map.tail('Click to add points to your area. Click the first point to finish the area.');
+        mode.map.tail('Click to add points to your area. Click the first point to finish the area.', true);
     };
 
     mode.exit = function() {

js/id/modes/draw_line.js

@@ -47,7 +47,7 @@ iD.modes.DrawLine = function(wayId, direction) {
         mode.map.surface.call(behavior);
         mode.map.tail('Click to add more points to the line. ' +
                       'Click on other lines to connect to them, and double-click to ' +
-                      'end the line.');
+                      'end the line.', true);
     };
 
     mode.exit = function() {

js/id/renderer/map.js

@@ -311,8 +311,12 @@ iD.Map = function() {
         return map;
     };
 
-    map.tail = function (_) {
-        tail.text(_);
+    var usedTails = {};
+    map.tail = function (_, once) {
+        if (!_ || usedTails[_] === undefined) {
+            tail.text(_);
+            usedTails[_] = true;
+        }
         return map;
     };
 

js/lib/d3.tail.js

@@ -53,6 +53,7 @@ d3.tail = function() {
     };
 
     tail.text = function(_) {
+        if (!arguments.length) return text;
         if (_ === false) {
             text = _;
             container.style('display', 'none');