Crash on Linux on specifying files with "fq" extension in the Tuxedo wizard

Scenario:

1. Open the Workflow Designer.
2. Open "RNA-Seq analysis with Tuxedo tools" sample workflow.
3. Select "Full" and "Paired-end", click "Setup" in the configuration wizard.
4. On the first page of the "Tuxedo Wizard" add a file with "*.fq" extension.
   Current result: a crash happens.
   Expected result: The *.fq files may be used as input.

Note that I was only able to reproduce the issue on Linux. And it is not reproduced if the files are renamed to *.fastq.