are you using the latest daily build 1.3.4, as there were some bug fixes regarding BuildEntityButton and EntityBaseDraggable added in this version? Did you also use the CONFIG += v-play_daily flag in your pro file (and make sure to run qmake and clean the project before, as another static library, the daily build one, is used)?
If these preconditions are met, could you please check if there are any errors or warnings in the log output?
One hint regarding your code:please do not use an anchors.fill for the colliderComponent you use for EntitBaseDraggable, as the collider size gets changed internally while the entity is dragged. We will fix this issue with the next daily build, but until then just set the width to your desired image size and use the anchor on the image not the collider, as we have done it in the StackTheBoxWithEditor demo for Obstacle: http://v-play.net/doc/daily/demos-stacktheboxwitheditor-qml-entities-obstacle-qml.html