Mounting an initially headless instance fails to initialise the renderer #2424
Mounting an initially headless instance fails to initialise the renderer #2424

Force the renderer to be initialised as the canvas renderer, unless a renderer other than 'null' is specified.  That may be the case if the consumer uses a custom renderer and remounts an already mounted instance to another container.  For most people, who use the default canvas renderer, the forcing of the canvas renderer on `cy.mount()` is fine.

cytoscape/cytoscape.js,cytoscape/cytoscape.js