Refine description of extension activation.

Author: chrfrantz

README.md

@@ -23,7 +23,7 @@ Example:
 
 ```
 ; Import extension
-extensions [dbscan]
+extensions [ dbscan ]
 
 ... instantiate agents with variable "wealth" ...
 
@@ -81,7 +81,7 @@ Example:
 
 ```
 ; Import extension
-extensions [dbscan]
+extensions [ dbscan ]
 
 ... instantiate patches with variable "resource" ...
 patches-own [ resource ]
@@ -122,7 +122,7 @@ Example:
 
 ```
 ; Import extension
-extensions [dbscan]
+extensions [ dbscan ]
 
 ... instantiate agents with coordinates ...
 
@@ -151,7 +151,7 @@ The preferred deployment variant is simply to use the auto-installation feature
 
 ### Variant 0 (requires NetLogo 6.1.0 or higher): Auto-Installation
 
-To trigger the installation, simply add `extensions [dbscan]` at the top of your model code and click on the `Check` button in the editor. NetLogo will then prompt you to confirm the installation of the extension and you can immediately use it in your code. You can manage the installed extension in the Extension Manager. For more details about the Extension Manager, see its official [documentation](http://ccl.northwestern.edu/netlogo/docs/extension-manager.html).
+To trigger the installation, simply add `extensions [dbscan]` at the top of your model code and click on the `Check` button in the editor. NetLogo will then prompt you to confirm the installation of the extension and you should be able to immediately use it in your code (Note: Sometimes a restart of NetLogo seems necessary to activate newly installed extensions). You can manage the installed extension in the Extension Manager. For more details about the Extension Manager, see its official [documentation](http://ccl.northwestern.edu/netlogo/docs/extension-manager.html).
 
 ### Variant 1 (requires NetLogo 6.1.0 or higher): Manual Installation via NetLogo Extension Manager