Color of weekend

Something has happened and my weekends on the Gantt are white - white over white the weekend columns do not show at all, only appearing where they cross the task bars.
How do I choose the color of weekends / days-off?

Please share the project file.

Hi Dmitry,
It happens in every file and when creating new ones, so I suspect it’s not project related.
Interesting is that the days of columns appear as a “shadow” around floating dialogue boxes!
See the following images
AND when I did the screen capture with Lightshot they magically appeared everywhere… (and dissappeared as soon as I completed the screenshot.

In this project weekend days are not defined. All days are working days. Project > Properties > Calendar.

You are right bad example but it’s not file related, I found out what it is!
I have a dual screen setup, my laptop screen has a resolution of 1920X1080 and my screen 2 is ultra-wide and has a resolution of 2560X1080.
Ganttproject (? or Windows 11?) does the scaling wrong between screens: when I drag the window from one to the next the width is proportionally wider, increases horizontal pixels and looses the color in vertical columns of the days off.
Below is a photo of GanttProject window floating halfway between screens:

Other apps in floating windows do not do that.
For example this is a spreadsheet (Open Office Calc) with the columns “striped” in red:

GanttProject is not aware of any drags between different screens and will not do anything with respect to this.

You may try a hack which was suggested in the context of another issue with high-resolution screens: Task font illegibile / aliasing in 3.2.3240

I was assuming no program is “aware”, that windows are handled by the operating system, Windows 11.

Yes, I’ve had the font issue and already have the extra lines of code in my setup file! (see the last post on that thread). Could that be messing up my columns?

I don’t think it is the issue.

Thanks, I’ll keep testing it and report back. It’s not such a major issue, now that I know when it happens and how to avoid it.
Big thanks! for being so responsive and for the great software

Just thinking… : it’s some form of draw-over that the app performs, I think, because as I said: if you float another window next to it, the columns re-appear in the “shadow” of the other window AND they appear when you are in print-screen/screen capture mode.
Maybe that can help you locate the issue?

There is no logic in GanttProject with respect to this. We build a view model of the chart (basically, calculate pixel coordinates of all graphic primitives which are relevant for the chart) and when Java /Swing decides that it is time to paint the window, we render the view model on canvas. We are not aware of any dialogs, screen resolutions, etc., at the moment of rendering.

Sorry, but I don’t think I will dig into this issue, especially given that I can’t reproduce it due to lack of such screen (and I am not sure that I would’ve been able to reproduce even if I had one).