My testing environment is Win 10, RAD Delphi 10.1 Berlin and IBO 5.7.13.2411. I am using two monitors.

 

A form has several TIB_LookupCombos (LC). No TIB_Grid is involved. Each LC has PopupAlignment = puAuto. Using the primary or 1st  monitor only the  LCs drop down as expected. If the form is on the 2nd monitor, when the LC list is dropped down it appears on the left side of the primary or 1st monitor. A problem. Changing to puLeft, puRight or puCentered causes the drop down list to be shown as expected. Reverting to puAuto brings the problem back.

I have set all the PopupAlignments to puCentered to avoid this problem.