Slider handles visible but disabled?

[Rob A.]

In order to make the Slider handles "active" I have to click on a selection Thumb (start or end) then the handles become active and I can user them to increase/decrease incrementally.

Is this "by design"?  If so, is there a way to prevent this default behavior and always have the Handles "active" (clickable)?

Cheers, Rob.

[Rob A.]

Add to this, issue is ONLY present when using Ranges.

[Dinko | Tech Support Engineer]

Hi Rob,

I am not sure that I have fully understood your scenario. I have tested this on my side and I was able to change the selection range using the mouse by clicking once on it. I don't have to click first on the handles to change the selected range. May I ask you to share the steps performed at your side so that I can follow them on mine? The code which I used is below:

<telerik:RadSlider x:Name="slider"  
    HandlesVisibility="Visible" 
    IsSelectionRangeEnabled="True" 
    Maximum="15" 
    Minimum="0" 
    SelectionEnd="8" 
    SelectionStart="5" />

Regards,
Dinko
Progress Telerik

[Rob A.]

Hi Dinko,

The issue is that the "range slider" should NOT need to "have focus" in order for the "handles" (not the Thumbs) to become enabled.

When IsSelectionRangeEnabled="False" the "handles" are always enabled regardless of control focus.  When IsSelectionRangeEnabled="True" the "handles (not thumbs") are NOT enabled until the range bar/thumbs have focus.

Cheers, Rob.

[Martin Ivanov]

Hi Rob,

I've tested Dinko's code snippet against your description, but I wasn't able to reproduce the issue. Can you check the attached project and let me know if anything should be added in order to reproduce the issue? Note that I've tested this with the default Office_Black theme (as in the sample) and with the Fluent theme.

Regards,
Martin Ivanov
Progress Telerik

[Rob A.]

Hmmm ... ok, perhaps I can clarify and maybe this is "by design" (although I can't see this as being a good design decision as it's not consistent when IsSelectionRangeEnabled="False").

The issue (when IsSelectionRangeEnabled="True":

In order for the handles (not slider thumbs) to be "enabled" (accept a mouse click via my cursor), I have to first select the thumb range slider via my mouse and that is when the handles will be enabled (accept mouse clicks).

Here is an unlisted video (I plan to remove in a few days for NDA reasons) showing the issue:

https://youtu.be/zkkbc4BTuOs

Hopefully it is more clear now.

Cheers, Rob.

 

 

[Martin Ivanov]

Hello Rob,

Thank you for the video. It helped me to confirm that we are on the same page with the issue at hand. However, I still cannot reproduce this in my sample application even when I change the theme to Green which I guess is the theme from the video. This said, my guess is that the original project uses an older version where something may be broken, or there is something specific in the application that is stealing the focus from the RadSlider element. If you isolate this in a runnable project or modify the one from my reply and send it over I can check it on my side and see what happens. 

Regards,
Martin Ivanov
Progress Telerik

[Rob A.]

Yes the Theme is Green using Xaml DLLs.  

The project DLL references are all from 2020.3.1019.40

There is NO code that changes "focus" anywhere in my application and as you can see from the video the problem of the handles not being enabled ONLY happens when the control does NOT have focus, once the control gets focus via the Thumbs the handles will then enable and stay enabled for the rest of my application session.

Your comment about "stealing the focus" doesn't really make any sense?  The control should not require "focus" in order for the handles to be enabled ... the same slider control doesn't require focus for the handles to work (enabled) when IsSelectionRangeEnabled=False.  

This is clearly an internal "initialization" issue with your slider control when "IsSelectionRangeEnabled=True".

Cheers, Rob.

[Martin Ivanov]

Hello Rob,

Thank you for the version information. 

About the "stealing the focus" I meant that something can capture the mouse, executes code that disables the control or something similar. Also, there could be a custom style that causing this. I am not telling that you've done something unintended in the application, but my point was that I've seen many unexpected or hidden behaviors coming from the specific setup of the application in combination with the control's implementation. Anyway, RadSlider should not require to have the focus in order to activate its handles and if it does that means there is an issue in the control or the application's logic. However, without reproducing this I cannot tell what happens. I've tested my project again with the corresponding version but still can't recreate the issue.

In order to be able to research this and find reason behind the troublesome behavior I will need to reproduce it on my side. To do so, it will be helpful if you can modify my project in order to reproduce this, or open a new support ticket from your telerik.com account and attach a sample project there.  

Regards,
Martin Ivanov
Progress Telerik