Subject: Re: [sdss3-25mlog 1875] Re: 2.5m obslog 20140831 (MJD 56901)
From: Russell Owen
Date: Tue, 2 Sep 2014 10:41:35 -0700
On Sep 2, 2014, at 9:40 AM, "John K. Parejko"  =
wrote:
> Finally had a chance to dig into this guider problem from two nights =
ago.
>=20
> I can't speak to why the observer's STUI buttons were greyed-out: =
Russell, do you have any idea what could cause that?
When things are working properly, a grayed out button as two basic =
causes:
- If you push a button, it will stay grayed out until the command is =
finished (succeeded or failed). A fairly common source of bugs there is =
that a command is never reported as done. Usually you can get out of =
that situation by pressing an "X" button, though if the actor that you =
are commanding is truly wedged then you may have to do more.
- Some buttons will be grayed out based on the reported state of an =
actor.
Of course STUI bugs can also contribute to the problem. However, the =
first pattern mentioned above is deeply ingrained into STUI's =
architecture, so bugs in that particular case are rare. The second case =
needs more custom coding, so bugs are less surprising.
Another source of bugs that sometimes affects controls on MacOS X is =
bugs in Tck/Tk. The usual thing I see there is buttons whose displayed =
state does not match its actual state (e.g. grayed out but should not =
be, and you can actually push them, or visa versa). I am looking forward =
to trying Tcl/Tk 8.5.16 once the binary becomes available. This likely =
fixes a long-standing crashing problem that has prevented my updating =
from 8.5.11, and brings a host of minor bug fixes. But I'll have to try =
it out before I know it's actually usable for STUI because Tcl/Tk is =
generally rather iffy on MacOS X. (Tcl/Tk is much more reliable on unix; =
over the years I don't think I have ever seen a Tcl/Tk bug on unix that =
was a significant problem for TUI or STUI).
-- Russell=