Annoying button border appear after tabbing

Sunny Sharma 1

We have a dotnet winform application which has form with different input controls along with Search button. If we just fill the input controls with data and navigate through different input controls using tabbing, it works fine and we expect the border around search button to appear while using tabbing but if we use a tabbing with all input controls and then later click on search button using a mouse hover, it has a black border which appears by default and we are unable to remove the border even by setting the value button.FlatStyle = FlatStyle.Flat;
button.FlatAppearance.BorderSize = 0;

Is there any fix that can be applied to remove the border around search button if we need to have tabbing in controls in place. I have seen number of posts but did not get any workable solution which satisfies both the tabbing and the removal of border around search button. Please note if we get border around search button while tabbing it's fine, it's only when we use tabbing and next time if we use mouse to click the search button it creates border around the search button which is causing issue.

Viorel 112.5K Reputation points

2022-11-10T06:54:16.637+00:00

Are you using the standard controls and forms?
Jiale Xue - MSFT 33,751 Reputation points Microsoft Vendor

2022-11-10T07:45:39.93+00:00

Is there any reproducible code? Is there a corresponding image?
Sunny Sharma 1 Reputation point

2022-11-10T14:10:44.48+00:00

Hi JialeXueMSFT-4441,

There is no code and we are using standard controls and forms.

Here are the steps to reproduce

Open a form in winform app in DotNetcore 6 and place some textboxes like Name Age, Address, Postcode and a search button

Set button properties to remove border
button.FlatStyle = FlatStyle.Flat;
button.FlatAppearance.BorderSize = 0;

Run the exe and use tabbing option to shift control from one textbox to another textbox

When the focus shifts on search button while tabbing you would see a black border around the search button
which is fine since we are using tabbing using keyboard

Now instead of tabbing , when we do a mouse hover over search button and click on the button, we again have a rectangular black border even though we have removed the border from the search button by setting it's bordersize property to 0;

Please note that if we run the application and doesnot use the tabbing option and hover over search button or click on search button , there is no border. The problem only happens once we use the tabbing option first and then later on use the mouse hover or click on search button to perform search operations where the border starts appearing which is not needed. We cannot get rid of tabbing since it's a requirement to have tabbing working to move focus from one control to another. Is there any solution to fix this issue?