Ext version tested:
Ext 6.5.0.775 Modern, Ext 6.5.1.345 Modern, Ext 6.5.2.463 Modern


Browser versions tested against:
Windows7 Chrome 58.0.3029.110


Fiddle:
https://fiddle.sencha.com/#view/editor&fiddle/28he


If a resizable panel is not floated or positioned, it will throw an exception when dragging northeast/southeast/southwest/northwest handles


Exception:
Code:
ext-modern-all-debug.js:130825 Uncaught TypeError: proxy[edge.splitPosSetter] is not a function
    at constructor.handleDragStart (ext-modern-all-debug.js:130825)
    at constructor.fire (ext-modern-all-debug.js:13597)
    at constructor.fire (ext-modern-all-debug.js:22989)
    at constructor.publish (ext-modern-all-debug.js:22952)
    at constructor.publishGestures (ext-modern-all-debug.js:23493)
    at constructor.onTouchMove (ext-modern-all-debug.js:23635)
    at constructor.publishDelegatedDomEvent (ext-modern-all-debug.js:23572)
    at constructor.doDelegatedEvent (ext-modern-all-debug.js:23015)
    at constructor.onDelegatedEvent (ext-modern-all-debug.js:23002)