[Lazarus] How to fix slow screen refresh of TListbox?

[Werner Pamler]

Am 11.11.2022 um 16:29 schrieb Bo Berglund via lazarus:
> You see that the buffer contains the complete log history from the start...

When the first block of data has arrived I would store the length of the 
buffer at this time. Then next time when new data come in, I would 
extract the "new data", i.e. the bytes between the stored length and the 
new length of the buffer and add them to the listbox. And store the 
current length for the next round. Etc... This avoids moving all the 
data to the listbox, which it already has, again and again. Because 
extraction of the individual lines in lbxRxdata.Items.Text := DataTxt is 
a length process.