Make keyboard more friendly

[smbea]

What should we do?

Make keyboard more friendly in event handling. It shouldn't force handle events.

Current behaviour:

• It intercepts during capture phase
  • Handles events even if component handles them
• Does not consider if element has tabIndex
• Input is not considered only in some cases:

  diagram-js/lib/features/keyboard/Keyboard.js

  Line 112 in 5f42235

  return isInput(event.target) && this._isModifiedKeyIgnored(event);

It should allow external component to handle their events nicely: if component prevents default, keyboard shouldn't handle it

Why should we do it?

Allow easier handling of events by components.