Interested in license issues please. (Score 1)

I contribute to "open / free" projects on my spare time. At work I develop / enhance "commercial" technologies. I would like to use more "open / free" development tools however licensing has consistently been an issue here. Q1: Can I use GNOME as a development environment for "commercial" development of proprietary processes and technology safely? ie: keep the secret stuff secret? Q2: Are there any costs either monitary or procedural I need to be aware of?