To hide all the buttons in Full Screen mode, you`ll need to add "!page-full-screen-mode" in the feature-id for the following shortcut-list in rwStandardToolbar.xml file located under \WEB-INF\xml\config. As displayed below.
<shortcut-list name="file1" feature-id="dhtml;!page-full-screen-mode">
<shortcut-list name="save" feature-id="!page-full-screen-mode">
<shortcut-list feature-id="show-apply-button;!page-full-screen-mode" name="Edit3">
<shortcut-list name="Data" feature-id="!page-full-screen-mode">
<shortcut-list name="zoom" feature-id="dhtml;rw-interactive-view-mode-eplus;!page-full-screen-mode">
<shortcut-list name="fullscreen" feature-id="!page-full-screen-mode">
Note: The document has to be saved in Full Screen Mode in order for this change to work.
Before the change:

After the change:

Code Customization:
WARNING:
This customization is provided as a convenience to Strategy users and is only directly applicable to the version stated. While this code may apply to other releases directly, Strategy Technical Support makes no guarantees that the code provided will apply to any future or previous builds. In the event of a code change in future builds, Strategy Technical Support makes no guarantee that an updated version of this particular customization will be provided. In the event of a code change in future builds, Strategy may not be able to provide additional code on this matter even though this customization is provided at this time for this specific build. For enhancements to this customization or to incorporate similar functionality into other versions, contact your Account Executive to inquire about Strategy Consulting assistance.
TS: 395056
Strategy Only End