A very simple plugin inspired by http://extjs.com/forum/showthread.php?t=33162

It appends a help message above or below a Field.

eg:



Code:
Ext.ux.FieldHelp = Ext.extend(Object, (function(){
    function syncInputSize(w, h) {
        this.el.setSize(w, h);
    }

    function afterFieldRender() {
        if (!this.wrap) {
            this.wrap = this.el.wrap({cls: 'x-form-field-wrap'});
            this.positionEl = this.resizeEl = this.wrap;
            this.actionMode = 'wrap';
            this.onResize = this.onResize.createSequence(syncInputSize);
        }
        this.wrap[this.helpAlign == 'top' ? 'insertFirst' : 'createChild']({
            cls: 'x-form-helptext',
            html: this.helpText
        });
    }

    return {
        constructor: function(t, align) {
            this.helpText = t;
            this.align = align;
        },
    
        init: function(f) {
            f.helpAlign = this.align;
            f.helpText = this.helpText;
            f.afterRender = f.afterRender.createSequence(afterFieldRender);
        }
    };
})());
CSS:
Code:
.x-form-helptext {
    font-size: 9px;
    color: #888;
}