Padding between panels in px. If padding is 0 the panels will be next to each other. If you change padding during run-time you will need to call .resize() method to resize to apply new padding.

Padding can be set during object creation: let layout = new w2layout({ name : 'layout', padding : 2, panels : [ { type: 'top', size: 40 }, { type: 'preview', size: 200 } ] }); Or any time after the layout has been created: w2ui.layout.padding = 2; w2ui.layout.resize();