The mentioned property will work only for a participant picker. Participant picker is used for searching users only. I believe, in your case you are using the top right hand global search, which can search across various objects.
There are various things that come to my mind as a solution/ workaround for your issue:
1. Are you doing an 'All Type' search with a*,t* as the criteria ? Is it possible for you to narrow down your search for specific objects ? For ex: Part and Document etc.
2. There are properties that let you have a predefinined number of rows to be returned. If the result set exceeds the number that is specified, a banner message is shown indicating that the search result more results that the limit.Following are the properties to be set in db.proeprties:
wt.pom.paging.snapshotQueryLimit
wt.pom.queryLimit
By default, these are set to -1 which indicates there is no limit to the result set returned. There are a few well written articles at PTC tech support to explain these proeprties in details.
3. From what I understand, you would like to restirict search if the number of characters entered are less tahn 3 or 4. Customization will be required to achieve this.
The Global Search is rendered using Twin Trigger field which is an EXTJS component. The rendering code can be found at -
<WT_HOME>\codebase\netmarkets\javascript\util\jsfrags\globalSearch.jsfrag
The line would look something like - twinField = new Ext.form.TwinTriggerField({ ....
There is a js function is globalSearch.jsfrag viz. loadSearch(...). This too might require a change.
Note: This customization will not work on the search page that is available through the navigator.
-Malavika