remove custom tab style rule when tab is closed

plugins/c9.ide.editors/tab.js

@@ -40,7 +40,7 @@ define(function(require, module, exports) {
                     }
                     amlTab && amlTab.setAttribute("class", this.names.join(" "));
                 }
-            }
+            };
             
             function initStyleSheet(fg, bg) {
                 var cssClass = plugin.name.replace(/[^a-zA-Z0-9\-_\u00A0-\uFFFF]/g, "-");
@@ -49,10 +49,14 @@ define(function(require, module, exports) {
                 rule = "." + cssClass + ".curbtn .tab_middle, ." 
                      + cssClass + ".curbtn .tab_middle::after, ." 
                      + cssClass + ".curbtn .tab_middle::before";
-                     
-                ui.importStylesheet([
-                    [rule, "background-color:" + (bg || "inherit") + ";"
-                     + "color:" + (fg || "inherit") + ";"]
+                if (!bg) bg = "inherit";
+                if (!fg) fg = "inherit";
+                
+                (
+                    ui.setStyleRule(rule, "background-color", bg, stylesheet) &&
+                    ui.setStyleRule(rule, "foreground-color", fg, stylesheet)
+                ) || ui.importStylesheet([
+                    [rule, "background-color:" + bg + ";" + "color:" + fg + ";"]
                 ], window, stylesheet);
             }
             
@@ -280,6 +284,8 @@ define(function(require, module, exports) {
             plugin.on("unload", function(e) { 
                 closed = true;
                 
+                if (rule)
+                    ui.removeStyleRule(rule, stylesheet);
                 // If there are no more pages left, reset location
                 var last = amlPane.getPages().length === 0;
                 if (last)

plugins/c9.ide.ui/lib_apf.js

@@ -3786,6 +3786,15 @@ apf.setStyleRule = function(name, type, value, stylesheet, win) {
     return !!rule;
 };
 
+apf.removeStyleRule = function(name, stylesheet, win) {
+    var rule = findCssRule(name, stylesheet, win);
+    if (rule) {
+        var i = Array.prototype.indexOf.call(rule.parentStyleSheet.cssRules, rule);
+        if (i != -1)
+            rule.parentStyleSheet.deleteRule(i);
+    }
+    return !!rule;
+}
 /**
  * This method gets a single CSS rule.
  * @param {String} name         The CSS name of the rule (i.e. `.cls` or `#id`).

plugins/c9.ide.ui/ui.js

@@ -636,6 +636,10 @@ define(function(require, module, exports) {
              */
             setStyleRule: apf.setStyleRule,
             
+            /**
+             * @ignore
+             */
+            removeStyleRule: apf.removeStyleRule,
             /**
              * @ignore
              */