Cannot click and drag sliders in Color Grading filter

What is your operating system?
Linux Mint 20 (Cinnamon Edition)

What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
20.11.28 (flatpak from flathub)

Can you repeat the problem? If so, what are the steps?
When making adjustments using the Color Grading filter, the vertical slider bars for Lift, Gamma, and Gain do not work properly. If you click and drag the sliders up or down, the slider can only be moved a short distance. Then what happens is that the whole UI for the Color Grading filter moves with the mouse pointer. You have to release the mouse button and start over. Same behavior occurs if you try to click and drag within the circular Lift, Gamma, and Gain areas. Happens every time. It’s only the Color Grading filter that has this problem. You can click and drag the horizontal sliders in the other filters and they work great.

I am not reproducing it on Ubuntu 20.04 with GNOME Shell using nvidia X driver, also using the Flatpak. I am not sure what is causing the issue. Are you using a mouse or some other touch or pen device? In any case, you do not need to drag these things; instead point and click.

I have the same problem on Windows 7 with a Huion pen tablet attached. I don’t have the problem on Windows 10 with just a normal mouse. So I suspect the tablet drivers.

I guess with a pen input you would need to raise and lower the pen to simulate point and click. What if the filters area is large enough to not need scroll bars? Does it work better then?

It happens both with an external bluetooth mouse or the trackpad on a Dell Precision 5520 and Dell Latitude 7490.

I just realized I made an error in my report. Both machines are fresh installs of Linux Mint 20.1 Beta (released a few days ago) not Linux Mint 20.

Let me do a fresh install of Linux Mint 20 and see if I can reproduce the problem there. I’ll report back.

I haven’t used my Windows 7 box much lately, and it was a few Shotcut versions behind. Exposing the entire Color Grading canvas (no scrollbars) did help noticeably. After upgrading Shotcut, the current version doesn’t have the problem at all. Maybe the Qt upgrade addressed something.

I decided to do fresh installs of Linux Mint 20 and Linux Mint 20.1 Beta in VirtualBox. I installed the same Shotcut flatpak in each instance and could not reproduce the problem in either virtual machine

So, it’s somethng special about my configuration with these two laptops and the problem only appears in this Color Grading filter UI.

I tried installing from the repository instead of using the flatpak. That gives me version 20.02.21. Same problem occurs.

I’ll play around more here to see if I can figure it out.

I did a fresh install of Linux Mint 20 (not beta) on the Dell Precision. Same problem. Then I did a fresh install of Pop!_OS 20.10 (GNOME 3) on the same machine. Again, same problem. That surprised me.

As a workaround, I can always just click instead of click-and-drag as you said.

I’ve also now tested on Windows 10 and the problem also appears there.

In summary, the vertical sliders do not work properly when tested on Linux Mint 20, Linux Mint 20.1 Beta, Pop_OS! 20.04 LTS, and Windows 10 on my Dell Precision 5520. This was also tested on a second test machine, a Dell Latitude 7490, where it failed when tested on Linux Mint 20 and Linux Mint 20.1 Beta. Tests were conducted using laptop trackpad and external bluetooth mouse on both machines.

The vertical sliders do work properly when tested within a Linux Mint 20 virtual machine using VirtualBox on Linux Mint 20 on the Dell Precision 5520.

The problem only appears when using the vertical sliders in the Color Grading filter UI. I see no problems anywhere else in the Shotcut UI nor in any other applications. The vertical sliders in the similar Lift/Gamma/Gain UI in Kdenlive 20.08.3 do work fine.

On my computers, the vertical sliders only respond if the mouse cursor stays within the slider area. If I click, hold, and move outside the boundaries of the slider box, it stops sliding until I bring the cursor back into bounds. This is fine for my purposes, but I wondered if it helped describe what you’re seeing on your computers.

I tested with the mouse pointer remaining within the slider area at all times.

I think it’s something to do with the custom controls in that particular filter UI (or something wrong with Qt that is causing that filter UI to break). As I can see for myself that it’s working fine in a VM, it doesn’t surprise me that it might be working fine for others on their actual hardware. By running tests on fresh Linux and Windows OS installs on my end, I think I’ve done all I’ve could to try to identify a possible configuration issue that might be tripping things up.

Same issue here.

Linux Mint 20 Cinnamon
Cinnamon version 4.6.7
Linux kernel 5.4.0-58-generic
Video NVIDIA Quadro K1100M
Shotcut 20.11.28 (AppImage from Github)

I just decided to try the current version (21.05.01) of Shotcut. I hadn’t been using Shotcut due to this issue. Even though I could work around it, it drove me a little crazy.

I’ve run some tests here and found that I can no longer reproduce the problem on my machines. The Color Grading filter UI works great for me. I don’t know if a change was made to Shotcut or if the problem was somehow being caused by my configurations here but whatever it was, the problem now appears to be gone.

Thanks for following up. We did make a lot of changes to upgrade our GUI library and adopt to its newer APIs, and those are probably the reason.

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