Hello every one:

     I have 3 form widgets in one screen and every form has 10 input widgets.The input in first form widgets are all readonly.

How can I do that coding  a css to make the input in first form background-color change to gray without uesing style classes at lower right corner.

I Wentao,

The Platform sets inputs with an Enabled set to False as readonly:

Thus, you can style it using the :read-only selector.

input:read-only {
    background-color: #ccc;

As for the "lower right corner", that's typically called the "Properties area", or just "Properties" :).