Have downloaded GXT 1.2.3 (twice - just to be sure) and unzipped the file. The resources/images folder looks like this:
In other words there is only one image in the entire images folder.
To make up the shortfall, I have copied images from Ext-2.0.2, which seems to keep most things happy (though trees look pretty ordinary), but I'd feel more confident if the download had the full set of css/images that are required.
It's actually a bit worse than just missing images. The ext-all.css file that comes bundled with the 1.2.3 GWT download is not fully compatible with the Java code - specially for trees. You can get a plausible ext-all.css from http://extjs.com/examples/css/ext-all.css.
You can get most of the missing icons from the ext download, but there are still a bunch of gxt icons that are not included in that which you will need to get from the showcase site - or email me and I'll send them to you.
If anyone from Ext is reading this, you need to understand that the GWT 1.2.3 download file is basically corrupt, presumably as the result of a broken build. If we could get to the subversion repository, we could probably sort this out for ourselves but that is available only to subscribers; so not-quite-open source.
I agree you cant use the ext-all from js. The problem is that the ext-all from js is the one that is included in the gxt 1.2.3 download. Once you get a gxt ext-all (as advised above), it refers to images that don't exist in the gwt 1.2.3 download because there are no images in the gxt 1.2.3 download. What I am trying to say is that the gxt 1.2.3 download file is corrupt. You only have to download it from http://extjs.com/products/gxt/download.php?dl=gxt123 and unzip it to confirm this.
I started off using the ext-all.css from resources/css, but this is virtually the same as the ext-all.css from the ext-js download. It does not contain any of the tree classes (e.g. my-tree-over, my-tree-open that are required by TreeItemUI). These tree classes are in tree.css, but not ext-all.css.
So what I am now using as an interim measure is the ext-all.css from the examples site (http://extjs.com/examples/css/ext-all.css) which does have the tree classes in it and is presumably the version that should be in the gxt 1.2.3 download.
And even with this version of ext-all.css, there are problems as described above because all the images are missing.
Please just download the gxt 1.2.3 sdk and unzip it and you will see what I mean.