Another feature request is now implemented on the "panzoom" branch on Github: removing element attributes via an input message.
The following demo shows to set an attribute "visibility" (with value "hidden"), and then removing that attribute via a second Inject button:
[{"id":"2399b014.7c6ad","type":"ui_svg_graphics","z":"4ae15451.7b2f5c","group":"2df28529.6748aa","order":2,"width":"12","height":"11","svgString":"<svg width=\"100%\" height=\"100%\" \n xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> \n <image id=\"my_request\" href=\"https://www.securitymagazine.com/ext/resources/SEC/2016/0216/SEC0216-edu-feature-slide1_900px.jpg\" height=\"100%\" width=\"100%\" preserveAspectRatio=\"xMidYMid meet\"/>\n</svg>","clickableShapes":[],"smilAnimations":[],"bindings":[],"showCoordinates":false,"autoFormatAfterEdit":false,"showBrowserErrors":false,"selectorAsElementId":true,"outputField":"payload","editorUrl":"http://drawsvg.org/drawsvg.html","directory":"","panEnabled":false,"zoomEnabled":false,"controlIconsEnabled":false,"dblClickZoomEnabled":false,"mouseWheelZoomEnabled":false,"name":"","x":1200,"y":720,"wires":[[]]},{"id":"6e24eeff.683db","type":"inject","z":"4ae15451.7b2f5c","name":"Remove attribute","topic":"","payload":"{\"command\":\"remove_attribute\",\"elementId\":\"my_request\",\"attributeName\":\"visibility\"}","payloadType":"json","repeat":"","crontab":"","once":false,"onceDelay":0.1,"showConfirmation":false,"confirmationLabel":"","x":980,"y":760,"wires":[["2399b014.7c6ad"]]},{"id":"196fb554.773beb","type":"inject","z":"4ae15451.7b2f5c","name":"Set attribute","topic":"","payload":"{\"command\":\"set_attribute\",\"elementId\":\"my_request\",\"attributeName\":\"visibility\",\"attributeValue\":\"hidden\"}","payloadType":"json","repeat":"","crontab":"","once":false,"onceDelay":0.1,"showConfirmation":false,"confirmationLabel":"","x":970,"y":720,"wires":[["2399b014.7c6ad"]]},{"id":"2df28529.6748aa","type":"ui_group","z":"","name":"Default","tab":"60e30c13.98a7e4","order":1,"disp":true,"width":"12","collapse":false},{"id":"60e30c13.98a7e4","type":"ui_tab","z":"","name":"Attribute add/remove demo","icon":"dashboard","disabled":false,"hidden":false}]
Of course I could also have set the attribute value to "visible", but you get the point ...
If anybody has a better use case for my readme page, please let me know!
Now pruning my hedges with 32 degrees Celsius ...
