Automation and Design Solutions
There is a better way.
Place Component Plus
This add-in adds a button to the drop down list under the Place button that allows you to choose a component, that is currently open in Inventor, from a list and place it into your active assembly.
In the Place Open Component Dialog box you can either select the component and then click the Place in Assembly button, or you can just double click on the component you want to place and it will place it into your assembly. To make selecting the right component easier, the dialog box will display a thumbnail preview of the component when it is selected.
How to use:
To use this add-in, in an assembly go to the Assemble Tab in the ribbon, then click the arrow underneath the Place button in the Components panel. Then click on the Place Open Component button. A dialog box will pop up displaying the names of all the currently open part and assembly files. Selecting an item will display the thumbnail of the component in the thumbnail box on the right side of the window. You can then either click the Place in Assembly button on the button right, or simply double click on the item to place it in your assembly.
To use this add-in you will need to be logged in with your Autodesk Account in Inventor.