Remove plans - uncheck Project once a plan is unchecked

Reproducing the issue:

1. go to "Bamboo administration >> Plans >> Remove plans"
   
2. select one Project in order to select all Plan within the project selected (i.e.: Support)
   
3. uncheck one Plan (i.e.: Plan A)
   
4. even after unckecking the Plan A, the project Support still checked. Consequently, you are not able to delete plan as the project should be unchecked.
   

In the example above, I have provided with a simple scenario where I have a Project with only 3 plans set up. If I really wanted to delete Plan B and Plan C, it would be required to check them individually and hit the delete button at the end.

Now, if I had 4 plans and wanted to keep only the Plan A, it would be required to check Plan B, Plan C and Plan D (please notice there were 3 clicks in this case)

As an improvement suggestion, I could select the project Support and then uncheck Plan A (in this case, it would be 2 clicks only).