message: [Qt] Stop using a solid white image as a border image
  This seems to be causing an issue on macOS, resulting in odd magenta
  pinstripes. Instead, just set the WalletFrame's background to solid
  white via hexcode.
diff: /****************************************************************************************/
  WalletFrame {
  -border-image: url(':/images/walletFrame_bg') 0 0 0 0 stretch stretch;
  +background-color:#ffffff;
  border-top:0px solid #000;
  margin:0;
  padding:0;
  