Listbox Strangeness - Scrollbars

I have a container with a listbox in it…
AutoHideScrollbars is FALSE
Horizontal and Vertical are both TRUE

the “gutters” for both scrollbars show on the control as expected.

When there are more records than the viewport can show (ie. when scrollbars should appear) there is a tiny little bit of what looks like the left end of a HORIZONTAL scrollbar but it is in the bottom of the VERTICAL scrollbar area… (ie… only the Vertical should have a scrollbar at this point)
Mousewheel scrolls the table properly, but there is no bar to drag

and if I resize the window (and thus resize the container), the scroll bar area AND the bottom area of the container all of a sudden contain random black lines (like TV snow)

macOS 10.11.6
Xojo 2016r4.1

another strangeness… in that bottom area. .I have a Label… this label moves to center itself as required… but in doing so, it leaves a copy of itself behind… are these related to some known or unknown “bug” with containers???

Ok… .as a band-aid… I put a CANVAS into the container and moved all the controls in IT… so the canvas is a “container” inside the container… I painted the canvas RED so I could determine what was showing or not…

In the above picture the “Vertical Scrollbar area” is RED (ie… transparent)
The “strange bits” are still there… but above that is transparent it seems… where the scrollbar “should be”
the anomly with the label has now gone away, I assume the canvas Paint event is taking care of that

also that “strange bit” is something… touching it with the mouse makes it change color (darker)


FYI… it happens under El Cap and Sierra both…
The Canvas under everything fixed the label and “snow” issues… but the Vertical Scrollbar just isn’t there…
as in its transparent

Here is the results after putting a canvas under all the controls and filling it with RED
The left image is the bottom left corner of the listbox, when it is just a bit wider than the sum of the columns
notice where the scrollbar should be is “RED” indicating it is “transparent” and showing the underlying canvas

the right image is just a tad less than the sum of the columns… note how here it seems to be showing remnants of cells from some unknown column .

Both images seem to have something that MIGHT be the scrollbar, but it is above the proper horizontal scroll (which does work as it should),


FYI… seems to work under WIndows :frowning:

It looks to me like the vertical scrollbar is there. It’s at the bottom and is turned sideways. Perhaps internally the width and height of the scrollbar are mixed up. I’m curious to see if the ‘little gray thing’ can be drug sideways. If so does that scroll the listbox?

I am assuming something similar… how ever… the question begs as to
“what would cause this to happen”?

and no it can’t be moved… I’ve tried… it DOES react when you touch it.

The only thing “different” about this listbox is that it is a child of a container control, and all its properties/events are channeled thru it via computed property

Strange. I’d like to try it later if I get a minute. Could you attach a sample project?

wish I could… but its part of a near 15k line program, and the custom control has too many dependecy (there is more than just listbox).

I am in process of saying “screw it”, and deconstructing the control, and seeing what happens then… but that is a ton of work…

I feel your pain. Tracking down the cause can be a time consuming affair. But the filing a bug report that is ‘not reproducible’ seems useless as well.