Index Max Extents are converted to 0 when altering the Index (4236200)

When altering an Index, if the Max Extents had previously been set as Unlimited, the Max Extents field becomes empty and the resulting script shows the Max Extents as being 0.
This causes the script to be invalid with an error, ORA-02221.

Steps to replicate:
        1.  Connect to Database
        2.  Go to Schema Browser | Indexes | Right-Click | Alter Index | Physical Attributes tab
        3.  See that the Max Extents dropdown has become empty (this was originally set to Unlimited)
        4.  If you change any other setting here and press Show SQL, the Max Extents show in the script as '0', which causes the script to become invalid if you run it. (ORA-02221)

WORKAROUND:
Fixed in v11 beta. Available from: http://toadfororacle.com/beta.jspa