Done, git master 64fd492c92e5be165e42332ef38d8d75e6c13298.
Normally proportional vertical scrollbar and thumbtrack is not possible with filtered datasets or lookupbuffers because the record count and "distance" between the items is unknown. odb_copyitems for t*dropdownlisteditdb loads a normal stringgrid with the filtered data, olb_copyitems for t*dropdownlisteditlb builds an index for the filtered datarows.
Currently there are artifacts with deo_livefilter without olb_copyitems.
Edit: Hopefully fixed in git master a858a4b9b6afca680ad24d9d54e807d15b468252.
Posted after 6 minutes 50 seconds:1. Choose a value in the list (from the attached example, 'vvv'), <Enter> - is set element 'vvvvvv'
2. Open the dropdown-list and ... the selected item is cleared.
As designed, the selected value is the value of the first column, the filter searches in the second column. If one clicks on the dropdown button one probably don't want to start with the value of the first column as filter because the list will be empty. Press Esc in order to restore the previous value.
Posted after 22 hours 36 minutes 5 seconds:git master 32eee9a24aa6b78d6533ec5756ca6346d6c0a2bd has a new onbeforefilter property, the example in MSEuniverse has been updated to demonstrate its use.