Can't change text frame font size in Slides

I am access a text frame of a slide using the findshape funciton but an unable to change the font size even using the pargraph and portions properties. I have also cast the type of the shape as a placeholder. I get not errors on the code but still the font does not change

Dim oNotes As Aspose.Slides.TextFrame = oSlide.FindShape("NOTES").TextFrame
Dim oPara As Aspose.Slides.Paragraph = oNotes.Paragraphs(0)
Dim port As Portion = oPara.Portions(0) 'Accessing the first portion of the paragraph
port.FontHeight = 15 'Setting the font height to 55
oNotes.Text = strNotes 'set the text

Dear jessick-dj,

Thanks for considering Aspose.Slides.

Change your code into like this, see the order of lines, it matters.

Dim oNotes As Aspose.Slides.TextFrame = oSlide.FindShape("NOTES").TextFrame

oNotes.Text = strNotes 'set the text

Dim oPara As Aspose.Slides.Paragraph = oNotes.Paragraphs(0)

Dim port As Portion = oPara.Portions(0) 'Accessing the first portion of the paragraph

port.FontHeight = 15 'Setting the font height to 55

You were actually setting the height back to default height, when you use TextFrame.Text property instead of Portion.Text property.