Transparency issues with #10Seattle ?

Transparency issues with #10Seattle ?

Update: Enabling Runtime Themes in Project Options, solves this issue.

I'm having some transparency weirdness issues which I find difficult to recreate in a SSCE.  In the attached image, you can see a login dialog in design mode at upper left, and some of it's properties at the right - and in the middle - the running dialog.  You see those three white spaces that is not in design mode?  That's TLabels that fail to be transparent.

In the .dfm, the highlighted label looks like:

  object lAppDetail: TLabel
    Left = 33
    Top = 82
    Width = 54
    Height = 14
    Caption = 'lAppDetail'
    Font.Charset = DEFAULT_CHARSET
    Font.Color = clInfoBk
    Font.Height = -12
    Font.Name = 'Tahoma'
    Font.Style = []
    ParentFont = False
  end

The labels are transparent when compiled with XE7.

Here comes the weird part: To make the label transparent again, I just uncheck and recheck the transparent property, which adds the transparent property.

  object lAppDetail: TLabel
    Left = 33
    Top = 82
    Width = 54
    Height = 14
    Caption = 'lAppDetail'
    Font.Charset = DEFAULT_CHARSET
    Font.Color = clInfoBk
    Font.Height = -12
    Font.Name = 'Tahoma'
    Font.Style = []
    ParentFont = False
    Transparent = True
  end

So - I try to recreate in an SCCE - I create a new form in XE7, add an image, add a label, set the same colors, etc. It's transparent when running in XE7.  I open the project in 10Seattle - and it is transparent when running there too! And there is no Transparent = True property in the .dfm.

Weird or what?