You can change the background colour of your QuickCarts using two different methods:

Method 1: Individual QuickCart editing Click the pencil button to enter Edit operation mode, then click the QuickCart you want to change. In the Edit QuickCart window, click the colour box next to Background colour to select a new colour. Click Use Default to revert to the default colour. Click OK to save your changes.

Method 2: Paint mode for multiple QuickCarts Click the paint bucket button to enter Paint operation mode. In this mode, when you click a QuickCart, its background colour will change to your selected paint colour. To change the colour that is painted, double-click the paint button to select a new colour. This method is useful for quickly changing multiple QuickCarts to the same colour.

PlayIt Cartwall only: You can also change the default colour for new QuickCarts by going to File > Settings and clicking Change next to Default QuickCart colour.