Html: Could input events be allowed while dragging?

Created on 23 Jul 2019 · 3Comments · Source: whatwg/html

https://html.spec.whatwg.org/multipage/dnd.html#drag-and-drop-processing-model

From the moment that the user agent is to initiate the drag-and-drop operation, until the end of the drag-and-drop operation, device input events (e.g. mouse and keyboard events) must be suppressed.

What is the reasoning for this? Are there any issues if it would be allowed to receive the press of key B?

A bad consequence of this restriction is that mousewheel can't be used to scroll pages or containers while dragging something.

I propose to at least allow mousewheel event. But I could also see use cases for other input. The user could grab an item out of the container, use keyboard shortcut to display another container and drop it in that one. Currently something like that would only be possible by catching dragover on some icon, just like scrolling is only achieved by dragging item close to the edge of the viewport.

P.S. Sorry if this has already been discussed. I couldn't find it in the tracker even though some bug reports refer to the standard - https://bugs.chromium.org/p/chromium/issues/detail?id=556169

additioproposal needs implementer interest drag and drop

Source

tontonsb

Most helpful comment

I don't have any apple devices. However reading various reports it seems that most large browsers dispatch wheel events on macOS, except Chrome.

As a Win user I'd be more thrilled to see the ban lifted for all platforms. Users seem to expect wheel to work in browsers as it has always worked with custom d&d implementations.

this behavior seems to match Windows, where no program allows scrolling or similar while dragging

This seems to be the case for the Office suite and it makes some sense as you can always select, cut and paste. But scrolling while dragging works in Paint. And that makes sense as well - you can't point your cursor to a position on a page there, it always pastes to the topleft corner. So scrolling works in Windows when it's necessary.

Shouldn't it be up to website developers to decide if wheel (or any other) events while dragging are necessary for their app?

tontonsb on 5 Aug 2019

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I'm not sure what historically motivated this decision. At this point, browsers seem to be interoperable in that regard, so it sounds like we'd classify this as a feature request. I'd be curious to hear from browsers if there are architectural reasons for this behavior.

domenic on 29 Jul 2019

Asking around a bit internally folks note that this behavior seems to match Windows, where no program allows scrolling or similar while dragging. But some preliminary reports say that on macOS you can scroll while dragging. Did you test on macOS? (I didn't, so the spec might not match reality there.)

domenic on 30 Jul 2019

I don't have any apple devices. However reading various reports it seems that most large browsers dispatch wheel events on macOS, except Chrome.

As a Win user I'd be more thrilled to see the ban lifted for all platforms. Users seem to expect wheel to work in browsers as it has always worked with custom d&d implementations.