ID 315509 - Parameter Find and Replace tab doesn't detect double underscores

Problem summary
When using the 'Parameter Find and Replace' tab to find certain parameter values in nodes, the function skips any Node which contains double underscores '__' when they are at the start of a node (e.g '__TEST').

This can be an issue when users arrange their Nodes by naming them with double underscores at the start.

Although it is broken for parameters, searching for Nodes with the 'in Node Name' option works as expected.

Additionally, if there is any letter or number before the double underscores, it works correctly (e.g ' A__TEST').

Steps to reproduce

1)  Create a Group Node and name it 'TEST'

2)  Add a string user parameter to the Node, name the value 'Test'

3) Duplicate the Group Node and rename it to '__TEST'

4) Open the 'Parameter Find and Replace' tab

5) In the tab, type in the value ('Test') and press the 'Find' button

Result: The first group named 'TEST' will appear with its value, while '__TEST' is missing.

Workaround
Editing the first value of the Node name to anything else will let it appear in the Viewer. 

Reproduced by support

Katana2.6v3 - Windows 7 - CentOS6.9
Katana2.6v1 - Windows 7 - CentOS6.9
Katana2.5v7 - Windows 7 - CentOS6.9
Katana2.5v1 - Windows 7 - CentOS6.9   
Katana2.1v6 - CentOS6.9

Earliest version tested
Katana2.1v6

Expected behaviour
The 'Parameter Find and Replace' should search for parameters in double underscored Nodes,

Actual behaviour
Nodes with double underscores at the start are not checked for parameter values,