Strange behaviour of PNGs with transparent background

[RobertoBozzolo · Accepted solution]

I have to revive this old thread since I have just found the reason for this odd behavior and it was totally my fault.

I have found that the faulty UIR file was saved in CVI 7.1 UIR !  

That version, as I remember, does not handle .PNG images: the final application can display them since the RTE does permit so, but it appears as if the transparency cannot be correctly handled in this case. I can't remember when and why I saved for such an old version a UIR developed and used in a 2009 application but that has very little interest now.

I was finally put on the right path when I noticed on a small service panel a control label not rotated as I should be.