Bug 125327 [Dialogs] Error message shown in the InputDialog is not fully visible
When an error message returned by InputValidator is long, InputDialog displays it partially. My suggestion is to create error label with SWT.WRAP flag, or something like this.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/InputDialog.java
}
    }
    /*
     * (non-Javadoc) Method declared on Dialog.
     */
    protected Control createDialogArea(Composite parent) {
        
        Composite composite = (Composite) super.createDialogArea(parent);
        
        if (message != null) {
            Label label = new Label(composite, SWT.WRAP);
            label.setText(message);
            GridData data = new GridData(GridData.GRAB_HORIZONTAL
                    | GridData.GRAB_VERTICAL | GridData.HORIZONTAL_ALIGN_FILL
                    | GridData.VERTICAL_ALIGN_CENTER);
            data.widthHint = convertHorizontalDLUsToPixels(IDialogConstants.MINIMUM_MESSAGE_AREA_WIDTH);
            label.setLayoutData(data);
            label.setFont(parent.getFont());
        }
        text = new Text(composite, SWT.SINGLE | SWT.BORDER);
        text.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL
                | GridData.HORIZONTAL_ALIGN_FILL));
        text.addModifyListener(new ModifyListener() {
            public void modifyText(ModifyEvent e) {
                validateInput();
            }
        });
        errorMessageText = new Text(composite, SWT.READ_ONLY);
        errorMessageText.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL
                | GridData.HORIZONTAL_ALIGN_FILL));