Multiple initializers for property 'dataprovider'

So, while migrating from Flex 3 to Flex 4, I'm going through the

• change namespaces
• move mx: to fx:
• wrap non-UIComponents into <fx:Declarations>

The next round of compiler errors is

"Multiple initializers for property 'dataProvider'. (note: 'dataProvider' is the default property of 'mx.controls.ComboBox').

Super useful error message here. 

Thanks to the hint at http://www.freeflowingcode.com/blog/flex/flex-multiple-initializers I noticed that there where still non-visual elements inside these components. 

Wrapping these elements into <fx:Declarations> made the error go away. 

So I guess that the take-away is, for components that use a dataProvider, and whose default property is dataProvider, you get a cryptic error message when your <Declarations> are not inside the correct tag. 

Showing more errors in Flash Builder / Eclipse

Have you had a task, like repackaging, migrating from Flex 3 to Flex 4, or anything that generated 100s of errors. Did you ever notice that eclipse had a "convenient" way of displaying 100 of (x+100) errors? I just discovered the simple way to show ALL of your errors.

Problems View -> Preferences (via down arrow on right hand side) -> Use Marker Limit = false;

Focusing on the spark Datagrid

From my presentation at 360Flex Unconference at Max.

The Slide Deck

Here is the blog that talks about the demo and has the source code:
The demo and source code