When last night hunting down that offset I saw with a few images, I found this code here still confuses me. Please add some comment why ```parentRect``` or ```parentRect``` can be undefined and why this seems not an error/problem (at least there is no is-error comment in the code or any logging output done, so one would assume all is fine in that case).
Just from what I understood both BCRs are needed to do a proper calculation, right? Please add some clarification.
Also not sure the calculation holds for frames which are not direct childs of <office:text>. It subtracts the offset between page/slide and parent element, but than that parent element might not be the offsetParent (think of <text:span> etc.), so the absolute x-offset calculated here will be wrong. Instead of parentElement the offsetParent has to be taken into account, I guess.