Steps to reproduce:
Create class:
<?php
class Foo 
{
} 
?>

Create class:
<?php
class Bar
{
    function test($obj)
    {
        if ($obj instanceof |
    }
}
?>

Invoke code-completion using <ctrl>+<space> at |

Result:
Only Exception classes are suggested

Expected result:
All known classes are suggested

---

Another case:

Create class:
<?php
class Foo 
{
} 
?>

Create class:
<?php
class Baz extends Foo
{
}
?>

Create class:
<?php
class Bar
{
    function test(Foo $obj)
    {
        if ($obj instanceof |
    }
}
?>

Result: 
Only Exception classes are suggested

Desired result:
Only Foo and classes inheriting Foo are suggested (in other words: Foo and Baz are suggested)


---

Environment:
Product Version: NetBeans IDE Dev (Build 201111080600)
Java: 1.7.0; Java HotSpot(TM) 64-Bit Server VM 21.0-b17
System: Windows 7 version 6.1 running on amd64; Cp1252; en_US (nb)
User directory: C:\Users\maghiel\.netbeans\dev
Cache directory: C:\Users\maghiel\.netbeans\dev\var\cache

---

Let me know if you want me to file an ENHANCEMENT for case 2.