Selected features tool don't work in QGIS 2.12

Question

I work with this polygon layer and features 6 and 7 are identical:

I don't understand why the selected feature tool work when i select feature number 7

and don't work when i select feature number 6?

Note: i copy/ paste feature 7 from feature 6

I red How to select features of visible layers in QGIS and that didn't solved my problem.

Answer 1

The last feature added to your layer will always be shown at the top (i.e. it will overlap any other feature). Which is why feature 7 is shown above feature 6.

If you want to select the feature 6 instead of feature 7, you could use the Identify Features tool then:

1. Left-click the duplicated feature
2. Right-click the top feature (which should be feature 6)

3. Select the Toggle feature selection option (which should now select feature 6):