FYI - I found the problem - thought I would pass the info along for posterity.
My issue was caused by custom header renderers - if every column used a custom renderer, then I would get this problem. Turns out my custom renderers were not setting explicitHeight or measuredHeight, so the mx:DataGrid.calculateHeaderHeight() would end up with a value of 0. Setting a value for measuredHeight on my custom renderer fixed the problem. In the cases where I had some grids that worked correctly, it turns out that they had at least on header renderer that extended mx:Checkbox or mx:DataGridItemRenderer. Apparently those classes return something for measuredHeight. Not sure what changed between Flex 2 and Flex 3.2 to cause this - some bug fix I guess. I've read the excellent blog on item renderers ( http://blogs.adobe.com/aharui/item_renderers/) and other sources about the component lifecycle, but I haven't found a discussion about requirements for custom renderers to set measuredHeight or measuredwidth - can anyonne elaborate on that topic? Thanks On Wed, Jan 7, 2009 at 10:18 AM, Glenn Jones <[email protected]> wrote: > I recently upgraded from Flex 2.0.1 to 3.2. I have a class that extends > mx:DataGrid. In Flex 3.2, some instances of this grid class are rendered > just fine, but some instances (about half maybe) are drawn incorrectly - the > first row of data values is drawn on top of the column header row. At least, > that's the visual result. > > So far I haven't been able to isolate a root-cause or even a good clue to > separate instances that work right from those that don't. > > Has anyone else seen something like this? > > I've reviewed the issues noted here: > > http://learn.adobe.com/wiki/display/Flex/Backwards+Compatibility+Issues > http://butterfliesandbugs.wordpress.com/page/2/ > > But I don't **think** any of them are related to this issue: > > - my flex2 code did not use/override DataGrid.drawHeaderBackground > - I've tried to locate and correct all of the changes for decreasing > rowIndex and rowCount/lockedRowCount by 1 > > Any suggestions are much appreciated. > > Thanks, > - Glenn >
