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DataGridView shuffling column widths depending on visibility when control is added

Both the 'Load' button on tabPage2 and the 'Load' Menu Item are running the same code, but as you can see in the demo above when the control is added when tabPage2 is not selected, the column widths shuffle despite it being the exact same code, the exact same control with the exact same content.
I'm not sure how relevant it is to the problem, but the UserControl I am adding looks like this:
Just a tab control with two tabs, a split container on the first tab with a DataGridView in the bottom split panel.
Each 'Load' creates a new tab page, a new user control, adds the user control to the tab page and then adds the tab page to the tab control on tabPage2.
Is there something at play here that I'm not aware of that would make controls render differently depending on their visibility when added?
EDIT: The DataGridView's are using DataGridViewAutoSizeColumnsMode.Fill

It does not have anything to do with the visibility of the tabs when adding the user control. To confirm you can keep the tabPage2 selected and you will see the same behavior as you currently have.
It is the selection and highlights of the tab controls that must be giving that notion. You can try adding around 4 user controls and click between tab2 and tab3 to confirm.

c# windows form Tab Order

I have a windows form in C# project that keeps Student Info. I caught the image:
I want to add data with sequential order as follows but when I enter data to Surname textbox, TAB button jumps to E-Mail textbox, then Phone Number textbox and lastly to Date of Birth DateTimePicker.
I made all control's TabStop property "False" on the form except these textboxes. And I arranged their TabOrder via Properties Section as follows 0,1,2.. as I intented. But the order followed as I wrote above. Then I opened Tab Order function via "View" on menu strip.. I clicked all controls which I wanted to use in order, but no use. The form and Tab button act as before. I caught Tab Order function image below:
What shall I do now?

TabIndex is important for controls which are siblings of the same parent. However, if your TextBox and ComboBox controls are each inside different parents then their parent controls must have the proper TabIndex.
In the Windows Forms Designer you can see which controls are children of which panels by bringing up the Document Outline. Go to View -> Other Windows -> Document Outline.
If each TextBox or ComboBox is directly inside a parent then its TabIndex doesn't matter, it can be 0. It's the parent (and possibly the parent's parent's) TabIndex which needs to be in order.

Now that we have VS 2019. Simply go to form.cs[design], click "View" tab at the top of the page and select "Tab Order". This will allow you to click on the form elements in order of which you want them to be tabbed to. Any items not selected will not be tabbable(I think I made this word up). Once complete, click "Tab Order" again to exit view.

Change panels / views based on button click

I would like to implement the following WinForms user-interface, with two buttons at the top that allows the user to toggle between two views.
So, when I click the 1st button ("Show User Profiles"), the three panels below should show the three different user profiles (with some content fetched from database), like so...
And when I click the 2nd button ("Show Chat History"), the three panels below should show the three different chat histories (with some content fetched from database), like so...
What is a good approach (either dynamic or static) to implement this kind of structure in C# / .Net? Is there a cleaner or at least more efficient way than my crude method below:
Layout three sets of controls for the three Profiles
Layout three sets of controls for the three Chat-Histories, overlapping on top of
the Profiles' controls.
Change visibility of the controls based on which button is pressed.
For example, if 1st button is clicked, Set Visibility=false for all the controls related to Chat-History, and Set Visibility=true for all the controls related to User-Profiles.

a tab control would give you a separate set of panels. Its the obvious way to do it, but if you want to overlay panels and control the visibility you can, and its fine. I have a content viewer that displays either images or text depending on the mime type of the content, and that context switching occurs without user interaction, so it makes sense there to put the image control on top of the textbox and set it visible if the mime type is image/jpeg. Where a user is going to make the choice tho, I would use a tab control.
I assume you are using the visual ui to add controls. you can just drag a tab control to your form and it should by default appear with 2 tabs defined. You can add more in properties my modifying the tabpages collection. That's where you would also rename them to reflect your choices (profiles, chats). drag the tab control up where you want it on the form and size it appropriately, or dock it to fill the form. drag 3 panels into the first tab, then click on the 2nd tab, and drag 3 more in there. then proceed as you would have. When the user clicks on the chat tab the tab control will manage the view - hiding the first tab and its 3 panels. Of course clicking the first tab would make that tabPage visible again. no need for you to code anything.
I'll just add that I don't understand the design of having 3 profiles visible, and 3 chat history's. Unless your users are going to be limited to 3 friends. I would think you would be better off using a listbox for friends names on the profiles page, with a single profile panel that just filled the profile controls based on which friend is selected, and then the same list on the chat page, with a single chat panel that loaded the history into the textbox based on which friend was selected. That way you can have all the friends you want :)
and for completeness i'll suggest one more way, why should the user have to switch between tabs to view a users profile or chat history when you can provide them both in a single tabPage? You could programmatically create a new tab for each user and on that tab have their profile panel on the left, and their chat history on the right. Less context switching = better user experience. The tab control will allow you to scroll for tabs that don't fit on the form automagically(tm).

How to easily reorder TabControl?

I have a TabControl which I have designed in the VS2005 designer that has about 7 tabs.
How can I easily switch the order of the tabs around?
I put one tab at the end in a rush, but now I want it somewhere in the middle.

In the properties of the tab control there's a TabPages collection. You should be able to shuffle them around in there. Just click the ellipses next to TabPages and a dialog will appear allowing you to move each one up or down in the order.

Mark the TabControl in the Designer.
In the Properties Window (F4) you have a TabPages Property.
You can open a new Window where you can reorder the TabPages.
If you want to do that at runtime you have to do
tabControl.TabPages.Remove(tabPage1);
tabControl.TabPages.Add(tabPage1); // add to the end
tabControl.TabPages.Insert(2, tabPage1); // add on specific position

Open FormName.Designer.cs.
Find the line this.tabControl1.Controls.Add ....
You can change the order here.
Screenshot

C# WinForm press tabs and it jumps all over the place

I have a WinForm program. In one screen it has several ComboBoxes, TextBoxes, and Buttons. How can I make it so that when the user presses tab, it will go through the fields in sequential order. Meaning from top to bottom? Or we can say "In my defined order"? So, for example, it starts with TextBox1, and then when the user presses Tab, it will go to the next TextBox, and when Tab is pressed again, will go to Button1, etc. etc.
Not sure if it’s possible, but for some reason pressing tab jumps all over the place. What defines the "tab"? what logic does it use to make it jump to the next field?

The TabIndex property of each control defines the tab order within a container (Form, GroupBox, Panel, etc). If you are working in the Visual Studio Designer, you can use the View --> Tab Order menu item to view/edit the tab sequence.

Each control has a property called TabIndex. When a user presses the Tab key, Windows cycles through each control in the order of the tab index. If two controls have the same TabIndex, they are selected in the order in which the controls were added to the Forms Controls collection.
It is also worth noting that if you have a control that can contain a group of controls within it's Controls collection (i.e. GroupBox), the tab processing engine will give tab focus to the parent control and then cycle through all of the internal controls, in their internal sorted order. This means that all child TabIndex values can be maintained independently of all other controls that are in the same collection as the parent control.

You need to use the TabIndex propert on the control. Be aware that according to the documentation, you must set the TabStop property to true in order for it to be included in the tab ordering.

You need to define the TabIndex of each control. There is a button in the designer toolbar to make it easier (I don't remember the name, but you should find it easily... it's probably something like "Tab Order"). Click this button, then click each control on the form in turn.

Each control has a property called "TabIndex". These will by default just be incrementing as you create items. You can set these manually.

Set the TabIndex: http://msdn.microsoft.com/en-us/library/aa984423%28v=vs.71%29.aspx

Please check out TabIndex property.