diff --git a/packages/client-app/internal_packages/plugins/lib/main.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/main.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/main.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/main.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/package-set.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/package-set.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/package-set.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/package-set.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/package.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/package.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/package.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/package.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/packages-store.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/packages-store.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/packages-store.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/packages-store.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/plugins-actions.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/plugins-actions.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/plugins-actions.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/plugins-actions.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/plugins-tabs-view.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/plugins-tabs-view.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/plugins-tabs-view.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/plugins-tabs-view.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/preferences-plugins.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/preferences-plugins.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/preferences-plugins.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/preferences-plugins.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/tab-explore.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/tab-explore.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/tab-explore.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/tab-explore.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/tab-installed.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/tab-installed.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/tab-installed.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/tab-installed.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/tabs-store.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/tabs-store.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/tabs-store.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/tabs-store.jsx
diff --git a/packages/client-app/internal_packages/plugins/lib/tabs.jsx b/packages/client-app/internal_packages_disabled/plugins/lib/tabs.jsx
similarity index 100%
rename from packages/client-app/internal_packages/plugins/lib/tabs.jsx
rename to packages/client-app/internal_packages_disabled/plugins/lib/tabs.jsx
diff --git a/packages/client-app/internal_packages/plugins/package.json b/packages/client-app/internal_packages_disabled/plugins/package.json
similarity index 100%
rename from packages/client-app/internal_packages/plugins/package.json
rename to packages/client-app/internal_packages_disabled/plugins/package.json
diff --git a/packages/client-app/internal_packages/plugins/styles/plugins.less b/packages/client-app/internal_packages_disabled/plugins/styles/plugins.less
similarity index 100%
rename from packages/client-app/internal_packages/plugins/styles/plugins.less
rename to packages/client-app/internal_packages_disabled/plugins/styles/plugins.less
diff --git a/packages/client-app/spec/themes/theme-manager-spec.coffee b/packages/client-app/spec/themes/theme-manager-spec.coffee
index 7eda6f30f..3361b4d34 100644
--- a/packages/client-app/spec/themes/theme-manager-spec.coffee
+++ b/packages/client-app/spec/themes/theme-manager-spec.coffee
@@ -32,7 +32,7 @@ describe "ThemeManager", ->
 
   describe "theme getters and setters", ->
     beforeEach ->
-      NylasEnv.packages.loadPackages()
+      NylasEnv.packages.activatePackage()
 
     it 'getAvailableThemes get all the loaded themes', ->
       themes = themeManager.getAvailableThemes()
diff --git a/packages/client-app/src/nylas-env.es6 b/packages/client-app/src/nylas-env.es6
index b57080833..e40da7ba3 100644
--- a/packages/client-app/src/nylas-env.es6
+++ b/packages/client-app/src/nylas-env.es6
@@ -379,12 +379,16 @@ export default class NylasEnvConstructor {
 
   _findPluginsFromError(error) {
     if (!error.stack) { return []; }
-    const left = error.stack.match(/((?:\/[\w-_]+)+)/g);
-    const stackPaths = left || [];
-    const stackTokens = _.uniq(_.flatten(stackPaths.map(p => p.split("/"))));
-    const pluginIdsByPathBase = this.packages.getPluginIdsByPathBase();
-    const tokens = _.intersection(Object.keys(pluginIdsByPathBase), stackTokens);
-    return tokens.map(tok => pluginIdsByPathBase[tok]);
+    const stackPaths = error.stack.match(/((?:\/[\w-_]+)+)/g) || [];
+    const stackPathComponents = _.uniq(_.flatten(stackPaths.map(p => p.split("/"))));
+
+    const names = [];
+    for (const pkg of this.packages.getActivePackages()) {
+      if (stackPathComponents.includes(path.basename(pkg.directory))) {
+        names.push(pkg.name);
+      }
+    }
+    return names;
   }
 
   /*
diff --git a/packages/client-app/src/theme-manager.es6 b/packages/client-app/src/theme-manager.es6
index b68bca8dc..d758bf692 100644
--- a/packages/client-app/src/theme-manager.es6
+++ b/packages/client-app/src/theme-manager.es6
@@ -4,6 +4,19 @@ import fs from 'fs-plus';
 
 const CONFIG_THEME_KEY = 'core.theme';
 
+/**
+ * The ThemeManager observes the user's theme selection and ensures that
+ * LESS stylesheets in packages are compiled to CSS with the theme's
+ * variables in the @import path. When the theme changes, the ThemeManager
+ * empties it's LESSCache and rebuilds all less stylesheets against the
+ * new theme.
+ *
+ * This class is loosely based on Atom's Theme Manager but:
+ *  - Only one theme is active at a time and always overrides ui-light
+ *  - Theme packages are never "activated" by the package manager,
+ *    they are only placed in the LESS import path.
+ *  - ThemeManager directly updates <style> tags when recompiling LESS.
+ */
 export default class ThemeManager {
   constructor({packageManager, resourcePath, configDirPath, safeMode}) {
     this.packageManager = packageManager;
@@ -116,7 +129,6 @@ export default class ThemeManager {
   }
 
   resolveStylesheet(stylesheetPath) {
-    console.log(stylesheetPath);
     if (path.extname(stylesheetPath).length > 0) {
       return fs.resolveOnLoadPath(stylesheetPath);
     }
diff --git a/packages/client-app/src/theme-package.coffee b/packages/client-app/src/theme-package.coffee
deleted file mode 100644
index 15a833cc8..000000000
--- a/packages/client-app/src/theme-package.coffee
+++ /dev/null
@@ -1,29 +0,0 @@
-Package = require './package'
-
-module.exports =
-class ThemePackage extends Package
-  getType: -> 'theme'
-
-  getStyleSheetPriority: -> 1
-
-  enable: ->
-    NylasEnv.themes.setActiveTheme(@name)
-
-  disable: ->
-    NylasEnv.config.removeAtKeyPath('core.themes', @name)
-
-  load: ->
-    @measure 'loadTime', =>
-      try
-        @metadata ?= Package.loadMetadata(@path)
-      catch error
-        console.warn "Failed to load theme named '#{@name}'", error.stack ? error
-    this
-
-  activate: ->
-    unless @isActivated
-      @measure 'activateTime', =>
-        @loadStylesheets()
-        @activateNow()
-      @isActivated = true
-    return Promise.resolve()