Hi @jiwanovski ,
Could you please share a bit more about your scenario?
Could you please show more details about the "LookUp window" that you mentioned? Is it the Dropdown list panel of the ComboBox?
Further, do you want to set the Color of the "LookUp Window" of the ComboBox to another color?
Based on the screenshot that you mentioned, I suppose that you add a Gallery control to list your all data source records, is it true?
Based on the issue that you mentioned, I have made a test on my side, and don't have the issue that you mentioned. The screenshot as below:
How do you color the first record within the Gallery in your app? Via the Fill property of the Gallery?
If you color the first record within the Gallery in your app via the Fill property of the Gallery, I think there is something wrong with it. Instead, please consider color the first record in your Gallery via the TemplateFill property as below:
then you could set the Fill property of the ComboBox to another color value you want to set. e.g. set the Fill property of the ComboBox to following:
RGBA(255, 255, 0, 1)
Note: The forth argument within above RGBA function could not be set to 0, otherwise, the Gallery's TemplateFill color value would override the Fill property of the ComboBox.
On your side, please consider add a Gallery control within your app to list all records from your data source, and add related ComboBox controls within the Gallery.
Best regards,