GTK Look and feel unacceptable on Linux...
Please continue to make native look-and-feel fidelity a major priority with Mustang. I'm running b67 and the GTK L&F *still* has major issues on Linux. My biggest complaint is font sizes not matching. Font sizes in native GTK apps are slightly smaller than Swing/GTK -- that is to say that Swing's GTK fonts are too big. The JMenuBar is also too tall.
Additionally, performance is an issue. I don't know if this is strictly due to the fact that GTK L&F is based on Synth or what. Resizing or maximizing a window is noticeably slow.
I love Swing, but SWT is the only way to go for writing Java GUI apps that are going to be run on both Windows and Linux. Swing on Linux *is* fast as long as you use Metal (Ocean) L&F. As soon as you try to shoot for native fidelity via the GTK L&F you stick out like a sore thumb and your performance lags.
I'm running a vanilla install of Ubuntu Linux 5.10 -- nothing tricky. The GTK "engine" is supported by Swing's GTK L&F.
I'm begging you to fix this. Native-looking apps on Linux is an absolute must. Forcing me to use Metal (as NetBeans on Linux does) is *NOT* a viable option.