As noted elsewhere there are two issues with component selection when editing models.

1/ Components are selected by cursor coordinates within the component-with-preview boundary, whether or not the preview is shown, i.e. a component is selectable by clicking on empty space if that empty space is within the boundary of the component if it were showing a preview, and

2/ Connections are selected by cursor coordinates within the shape formed by the connector curve and a boundary closing straight line between the ends, and connector selection takes priority over component selection such that, if a connector curve closed-boundary shape passes over a component, it may be difficult - or even impossible - to select the component.

For all but the most trivial models of a few components in a straight line, this makes selection problematic.

Two fixes:

2/ Allow the user to select e.g. straight line connectors so that the closed-boundary shape is the connector itself and component masking cannot occur.

Selection behave the same for click select and marquee drag select.