[Bug 1.67] Error when buying a blueprint slot

In the 1.67 version released today, there is a regression bug. When clicking on a blueprint slot to buy it, an error pops up.

Error message:

Assertion failure:…\src\GUI_SlotPlacer.cpp 111 - Error: [Unknown error]

After closing the error message, everything works fine, the slot is placed.

Addendum: no bug when buying Research Office (not tested for other facilities).

Thanks, I shall investigate…

found it, and will fix today! Thanks for reporting it.