 With shift pressed, clicking the background should not unselect elements #1133
 With shift pressed, clicking the background should not unselect elements #1133

rlugojr/cytoscape.js,soomin-maeng/cytoscape.js,KonstantinShemyak/cytoscape.js,KonstantinShemyak/cytoscape.js,rlugojr/cytoscape.js,soomin-maeng/cytoscape.js