When and how to use "lock messages"

[François Vanzeveren]

Hello all,

I am confused about when to use the statement ³lock messages² in setProp
handlers. I found the explanation in the User Guide very unclear.
Page 183, the statement "lock messages" is used in the example "lastChanged"
to prevent recursion. On the same page, the exemple "percentUsed" does not
use the statement... I do not understand the difference between these
exemples. I would have expected to use the statement in "percentUsed" as
well in order to prevent recursion.

Thanks for your help.

François