AutoHide pane headers feature does not account for real pane header height

[ddaribo]

Is your feature request related to a problem? Please describe.

This request is coming from a customer.
The height of headers is changed through styles, for example:

 igc-dockmanager::part(pane-header) {
    background-color: red;
    max-height: 15px;
    min-height: 15px;
  }

and the showPaneHeaders property of the component is set to onHoverOnly.

However, the hover area to display the header when mouse is over it does not correspond to this set height.
Sample

Describe the solution you'd like

The hover area to match the actual pane header size.

Describe alternatives you've considered

Cannot be worked around on app level.

Additional context

Currently, the pane header height is hardcoded as a constant (ref. here):
const PANE_HEADER_HEIGHT = 40;