"Switch to resource selection" option when editing operation step

[HelenClifton]

Expected behavior

Select an operation. "New Operation Step" window opens. Expect to be able to select different parameters.

Actual behavior

Parameters which are NOT of type Dataset have a toggle switch next to them which gives the option to "Switch to resource selection" . When this is selected, a drop-down list is shown but it is not possible to select any resource. In any case, it does not make sense to select a resource for certain parameters such as string types.
Same behaviour is seen in "Edit Operation Step" window.

Steps to reproduce the problem

The example is given for coregister operation, but the same is seen with other operation types.

1. Open cate GUI and ensure that at least two resources have been created in the workspace.
2. In Operations panel, double-click on an operation, e.g. coregister.
3. In the New Operation Step window, verify that a resource can be successfully selected for a parameter of type Dataset (ds_master and ds_slave)
4. In the New Operation Step window, select the "switch to resource" next to parameter method_us (type string)
5. In the New Operation Step window, select the "switch to resource" next to method_ds (type string)

6. Observe a "select resource" drop-down list is seen but it is not possible to select any resource.

Specifications

Cate 0.9.0-dev.4
Windows 7 Professional

[mzuehlke]

A resource may provide a string, too. But you are right the current behavior is not straight forward.
Now the switch is only enabled when the drop-down box would contain any compatible resource.