Display issues in TLMDListBoxExt

Luis Thé

There's an issue when resizing a form that includes a TLMDListBoxExt with multiple columns/headersections, the data will return back to the first HeaderSection (even if the user has scrolled to the middle, but the scrollbar doesn't return back to its original position. Hence there's an 'overscroll' issue (to a blank region beyond the data), if you now scroll back to the initial position.

Delphi 10.3, LMD Tools 2022.4

Luis Thé

I also noticed a similar issue when resizing a HeaderSection as well. If you resize a header, then the first header will suddenly increase to a very large size and the same overscroll issue occurs as well. I reckon there might be a problem with the scroll tracking relative to the data. 

Luis Thé

I have attached some screenshots concerning the situations mentioned above.

Luis Thé

The expected correct outcomes are: the HeaderSections shouldn't go back to the first one when the form is resized and the scrollbar shouldn't return back to initial position (while the data view doesn't move) when the form containing the TLMDListBoxExt is resized.

Eugene Balabuev (LMD)

Thanks for report. I'll check.

Luis Thé

Great. Will verify this once I get the next minor release and give you an update.

Luis Thé

Tested with the new release, but the issue still occurs. Also if you move a HeaderSection that is on the middle, the data doesn't move with it.

Please refer these screenshots.

Luis Thé

There is also this procedure included in my project related to this unit, but I'm not sure whether it works correctly.

(lBoxSummary is the TLMDListBoxExt object)

procedure TFormBatchResults.lboxSummaryHeaderSectionResize

  (HeaderControl: THeaderControl; Section: THeaderSection);

var

    i, Width: integer;

begin

    Width := 0;

    for i := 0 to FColCount - 1 do

        Width := Width + lboxSummary.HeaderSections.Items[i].Width;

    HorzScrollBar.Range := Width + 1;

    // Sets horizontal scroll bar

end;

Luis Thé

Please check the new comments mentioned above.

Eugene Balabuev (LMD)

It works fine in my simple test project. So, can you please provide a small demo (including your HeaderSectionResize event handler) and steps to reproduce the issue.

Eugene Balabuev (LMD)

Fixed.