The mouse scrolling event was blocked without holding down ctrl

[Himiaomiao]

Describe the Bug

The parent component on the page can scroll the page. If the Ctrl key is not held down on the. djs scrollable class to scroll the mouse wheel, it will prevent all scrolling events from occurring, resulting in the page being unable to scroll and the process view being unable to zoom in and out, giving the user the impression that the mouse has failed

Steps to Reproduce

Steps to reproduce the behavior:

1. Create an element with a scrollbar and place the flowchart component in its child nodes.
2. Scroll the mouse over the flowchart display area (without holding down ctrl)
3. Scroll the mouse over the flowchart display area (hold down ctrl)

If possible, try to build a test case that reproduces your problem.

Expected Behavior

A clear and concise description of what you expected to happen.

1. When the mouse scrolls the page without holding down ctrl, the parent element scrolling event is triggered
2. Hold down the ctrl mouse to scroll through the flowchart to zoom in and out

Environment

Please complete the following information:

• Browser: [e.g. IE 11, Chrome 69]
• OS: [e.g. Windows 7]
• Library version: [e.g. 2.0.0]

[Himiaomiao]

Suggest adding a judgment in the handleWheel function of the ZoomScroll.js file
if(event.ctrlKey){
event.preventDefault();
}

[nikku]

@Himiaomiao we could add this as a feature request, however you could also consider something like the following:

• require explicit focus of the modeler to scroll, allow the user to unfocus via ESC or TAB

[nikku]

Moving this to our backlog.