Sometimes these are made from something called 'layered windows'. By default, FlashBack does not record these because doing so can cause some performance issue.

However, you can enable recording of layered windows by doing the following:

  1. Click Settings
  2. Select the Record Mode / Performance tab
  3. Click More Settings... 
  4. Enable the 'Capture layered windows and tooltips in GDI and MPEG mode' option.