If you are developing code components (PCF) for canvas apps you'll be used to using the 'Get more components' panel. When adding the code-component to the canvas app, occasionally you will receive the somewhat unhelpful error:
Couldn't import components
There are no more details provided in the expanded down arrow area:
I'm putting this here for my future self (who always seems to forget about this issue) and anyone else who comes across this error.
The cause is usually because you have a property-set that has the same name as an in-build property or one of your own (e.g. Enabled/Selected)
The resolution is simply to prefix your property-set names with the name of the data-set:
<data-set name="Items" ... >
<property-set name="ItemsSelected" .. />
<property-set name="ItemsEnabled" .. />
</data-set>
Hope this helps!