Repost: Column marking has visual artifacts when marking blocks containing spaces

[Claus Pedersen]

This is a repost from the PLD beta forum:

I have the following code in a program window:

x  yz w
x     w
x  yz w
x  yz w

I place the cursor in the first line at the first space after x and use column marking to mark the 2 spaces in all 4 lines between x and y. The column marking at line two is now a little wider than the rest (a funny bulge to the right).
I extend the column marking one column further to the right and reduce the column marking back to two columns again. Now the column marking at line 2 covers three spaces whereas the rest of the lines cover two spaces as expected.
I delete the w's (incl. the resulting traling spaces) and make the same marking again. Now the artifacts are the other way around: line 2 has one marked space, whereas the others have 2. If you Alt-Tab to another program and the back to PLD again, the artifacts partly disappear, so it seems to have something to do with updating of the screen.

 

[Claus Pedersen]

Update:

it looks like the extra visual space in line two is a screen update artifact. When I shift to other PLD windows (e.g. a program window), the image content of that window is 'left behind' in the extra erroneous space. E.g. the code content pane from another program window can be seen in the edited window.