mouse wheel events are not being fired during a drag

[maribethb]

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Description

title

this is needed for scroll-options to work

Reproduction steps

1. Attach this event listener to the playground in core:

    Blockly.browserEvents.conditionalBind(
         workspace.getSvgGroup(),
         'wheel',
         this,
         () => {
           console.log('mouse wheel event');
         });

2. open the console
3. scroll the mouse wheel, observe the logs
4. pick up a block to drag it
5. scroll the mouse wheel, observe the lack of logs

Stack trace

No response

Screenshots

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Browsers

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[maribethb]

surprisingly, this css change is causing it https://github.com/google/blockly/pull/7999

[maribethb]

The drag layer is not a child element of the workspace.getSvgGroup() element where we were previously attaching the event listener. If the drag layer captures an event, it will be bubbled up, but the svg group won't get it because it's not a parent of that element.

Before the change in 7999, the drag layer wasn't capturing events. After that change, it does capture events (including, apparently, wheel events despite the name of the css property).

So the scroll option plugin should put its event listener directly on the drag layer.

So consider this issue to be that core should provide a getter for the drag layer. for now in scroll-options i can get the layer through query selectors.

[bsampada7]

Can I work on this issue @maribethb?

[BeksOmega]

Can I work on this issue @maribethb?

Hiya @bsampada7 I don't think we quite know how we want this to work yet. The list of help wanted issues is probably a better place to look for things to work on! Let me know if there's something specific you're interested in and I can try to match you with an issue =)