Why is double-click necessary to select components

When components require a double-click to select them, the component is usually locked. Users generally lock components when they want to keep the component in its current position and rotation. Requiring a double-click to select a locked component helps to prevent accidental moving or dragging of a component. 

Starting in Version: 18.0
Up to Version: Current

Solution Details

Usually, a component can be unlocked in the properties panel. Just double-click to select the component, and then navigate to the properties panel. In the properties panel, under the Location section, the lock icon can be selected to toggle the locked behavior. Once the component is unlocked, a single click should now select the component. 

If the component is unlocked in the properties panel and still requires a double-click to select it, it may be locked by a room in the PCB. To confirm this, check in your design rules for any “Room Definition” rules (Design ► Rules ► Placement ► Room Definition). If any of your Room Definition rules have the “Components Locked” check-box checked, this is likely the cause of a component being locked. 

To unlock the components, just un-check the “Components Locked” checkbox, or change the “Where The Object Matches” query to exclude the component that you wished to be unlocked. 

In the screenshot below, any component in the component class “16MHz_Clock” will be locked.