Currently it is not possible under ODF v1.2. The cross-reference feature makes use of either bookmarks or reference marks as described under §6.2 (anchoring part) and §7.7.5-7.7.6 (citation part). The two methods are similar in that both offer elements for a point anchor (
<text:reference-mark>) as well as a pair of elements for a range anchor (
<text:reference-mark-end>). These destinations can then be cross-referenced by a citing element (
<text:reference-mark-ref>). The definitions all state that each is usable within the following elements:
<text:a>, <text:h>, <text:meta>, <text:meta-field>,
<text:p>, <text:ruby-base>, and <text:span>.
In the case of a cross-reference to a heading, for example, a bookmark will be used. On the other hand (because it is not possible to insert an anchoring mark directly into a frame), setting an anchor in the text adjacent to a frame (via Insert > Cross-reference… > Cross-references tab > Set reference and pointing to the named Draw object) results in a reference-mark being used. This is not ideal though and is little different to using any other type of text element (e.g., caption, heading, etc.) as a substitute anchor. In order for a cross-reference to be made to a Draw object (text box) or Text frame, ODF will first have to be extended to allow for the indicated tags to be usable within the
<draw:frame> element (which encloses the
You can drag-n-drop a Draw object entry from the Navigator to the text and create a hyperlink to the object, however this also does not appear to be working (it may be related to fdo#36310 as I indicate in my answer here). A possible partial workaround is to use a Text frame (Insert > Frame…), as that is effectively what a text box is anyway. Text frames inserted via the menu indicated are automatically numbered / named, and while they are a little more cumbersome to use, the drag-n-drop from Navigator does produce a viable hyperlink, but again, are not currently cross-referencable.
 Any Extended version of ODF could be altered in the interim to incorporate the required changes, as these versions of the specification are designed to allow for temporary including of additional features.
 Hyperlinks make use of the
<text:a> element rather than the cross-reference elements indicated.