I think, the watch property Value (of variable) should be only `read`.
If I try to modify this property during debugging, the message window with caption Exception and text `Exception in setter method of property: Value` appears.

[IAN] It *should* be possible to modify watches during debugging - the only interesting thing here is the exception, which you did not include...

[Dan]
1) Using Standard Debugging, when I try to modify a local variable, the following exception is thrown:     (and the previously described message window appears)

java.lang.IllegalArgumentException: This version of the debugger does not support changing the value of static or local variables.
        at com.netbeans.developer.modules.debugger.debug.ToolsVariable$1.protect(ToolsVariable.java:143)
        at com.netbeans.developer.modules.debugger.support.util.Protector.run(102)

        at com.netbeans.developer.modules.debugger.support.util.RequestSynchronizer$1.run(62)

The modification of a nonlocal variable is OK (it works).

There is a small inconsistence - add watch for nonlocal variable two times, stop debugger, edit the first watch - a new value is displayed, but the second watch displays the old value. It is OK after
Debugger is runned and stopped again.

2) Using JPDA Debugging - nonlocal variables cannot be modified. They stay unchanged if I try to enter         a new value.