attachment opening does not grab focus

Running LO 64bit in WIN 7 Pro My Thunderbird mail agent (45.2) uses Calc to open .xls attachment in an email.
Should not Calc grab screen focus when it opens the attachment? As it is, the opened spreadsheet is completley hidden by the Thunderbird message screen. In this circumstance some of my colleagues wrongly think opening the attachment has failed. I acknowledge that this may be a Thunderbird issue, but I suspect Calc should be more of a stand up ap in this circumstance!

This is a known bug 75471 that is fixed in LO 5.4.

Also, as mentioned by developer in abovementioned bug, this can be fixed in any older version by going to Tools->Options->Advanced->Expert Configuration, searching for ‘ForceFocusAndToFront’ and double-clicking to change it to ‘true’.