DROOLS-909: KIE Workbench: ExpressionBuilder does not include all MethodInformation's in selector

When trying to use "Expression editor" in the guided rule screen of the web app, combining with restrictions on String fields which use functions like "toLowerCase" , "toUpperCase" -
Expression editor leaves a blanc field to fill and if left blanc - KIE automatically fill it with "" - and rule doesn't get compiled.

So instead of getting for example;
1. | package ido.droolsrules.dqsrulesqa;
2. |
3. | import java.lang.Number;
4. |
5. | rule "Test Camera Model"
6. | dialect "mvel"
7. | when
8. | cam1 : Camera( brand.toLowerCase() == "sony" )
9. | then
10. | cam1.setLens( 5.0 );
11. | end

Rule is generated (In source tab) as:

1. | package ebay.droolsrules.dqsrulesqa;
2. |
3. | import java.lang.Number;
4. |
5. | rule "Test Camera Model"
6. | dialect "mvel"
7. | when
8. | cam1 : Camera( brand.toLowerCase("") == "sony" )
9. | then
10. | cam1.setLens( 5.0 );
11. | end

view line 8 to spot difference.