The following definition of the textbox in the underlying aspx page:
~\CMSModules\Content\CMSDesk\Properties\Alias_List.aspx
<asp:TextBox ID="txtAlias" runat="server" CssClass="TextBoxField" MaxLength="50" />
You can change it there to allow more characters, or set it in the codebehind, where you would try to get the settings key value from webconfig, and optionally default the value to standard 50 chars. There are more limits that are put together. Basic ones are for NodeAliasPath - whole alias path must be less than 450 chars long, and then NodeAlias (one level). There's also a Document name field length and DocumentUrlPath (that's used as live url). Generally, you can have longer names in URL by manually setting "Custom URL Path", which is also good for trimming the really long URLs in the desired place (and not in the middle of the word...).
Following two keys that can be used in web.config file (and are described at
http://devnet.kentico.com/docs/devguide/web_config_parameters.htm) and the related comments should explain this a little bit:
CMSMaxNodeAliasLength
Maximal length of a document's node alias. The default value is 50 characters and larger names are trimmed. This key can be used to increase the length - useful for long node aliases. If you use the key, you also need to set the size of the 'NodeAlias' column in the 'CMS_Tree' database table to the same value. However, the maximal length of 'Node alias path' is 450 characters, so documents deep in the tree will have the 'Node alias path' trimmed anyway.
The default value is 50.
example of usage:
<add key="CMSMaxNodeAliasLength" value="120" />
CMSMaxNodeNameLength
Maximal length of a document's node name. The default value is 100 characters and larger names are trimmed. This key can be used to increase the length - useful for long node names. If you use the key, you also need to set the size of the 'NodeName' column in the 'CMS_Tree' database table to the same value.
The default value is 100.
You might be thinking about using "Use name path for URL path" setting. This is good, however the same trimming as for NodeAlias is performed here - using CMSMaxNodeAliasLength limit.
The best thing would be probably to make some strings of particular length 51 / 101 and so on ... and after setting the keys (and DB fields), checking if the behavior of shortening suits your needs.
Best Regards,
Edward Hillard