New tab not opened if a New Tab button is clicked at the first instance when only pinned tabs are available in vertical tab view

[MadhaviSeelam]

Description

Found while testing #43375. Created all pinned tabs in a vertical tab view. Pressed New Tab button (and other ways Pressed +, Ctrl + T) to open a new tab but the new tab is not shown in the vertical tab view although page refreshed/animated. However new tabs opened subsequently after pressing New Tab button. Works as expected if there is at least one unpinned tab

Steps to reproduce

1. Install1.75.172
2. launch Brave
3. open few tabs
4. enabled vertical view
5. pin all of the tabs
6. press New Tab button

Actual result

Nothing happens. No new tab opened.

2025-01-31_09h53_57.mp4

Expected result

Tabs should be opened at the first instance when there are only pinned tabs.

2025-01-31_10h11_02.mp4

Reproduces how often

Easily reproduced

Brave version (brave://version info)

Brave	1.75.172 Chromium: 133.0.6943.39 (Official Build) (64-bit)
Revision	92995c24e269fce1f4da632a4f0462458474866e
OS	Windows 11 Version 24H2 (Build 26100.2894)

Channel information

• release (stable)
• beta
• nightly

Reproducibility

• with Brave Shields disabled
• with Brave Rewards disabled
• in the latest version of Chrome

Miscellaneous information

@rebron @simonhong

CC: @brave/qa-team

[simonhong]

checking.

[simonhong]

Found more bug scenarios from same reason.

STR 1.

1. Turn on vertical tab mode
2. Open one window(A) and make it have one unpinned tab
3. Open another window(B) and make it have one pinned tab
4. Move window B's pinned tab to window A via pinned tab's context menu (Move tab to another window)
5. window B's pinned tab is moved to window A but it's not visible in window A

STR2.

1. Turn on vertical tab mode
2. Open one window(A) and make it have one unpinned tab
3. Open another window(B) and make it have one pinned tab
4. Move window A's unpinned tab to window B via pinned tab's context menu (Move tab to another window)
5. window A's unpinned tab is moved to window B but it's not visible in window B

[simonhong]

Our VerticalTabStripRegionView tries to re-layout both tab containers(pin & unpin) when it gets child's preferred size changed noti.
However, upstream doesn't give that noti when first tab is added.

Tab* TabContainerImpl::AddTab(std::unique_ptr<Tab> tab,
                              int model_index,
                              TabPinned pinned) {
  // First add the tab to the view model, this is done because AddChildView sets
  // some tooltip information which tries to calculate the hit test, which needs
  // information about its adjacent tabs which it gets from the view model.
  AddTabToViewModel(tab.get(), model_index, pinned);
  Tab* tab_ptr = AddChildView(std::move(tab));
  OrderTabSlotView(tab_ptr);

  // Don't animate the first tab, it looks weird, and don't animate anything
  // if the containing window isn't visible yet.
  if (GetTabCount() > 1 && GetWidget() && GetWidget()->IsVisible()) {
    StartInsertTabAnimation(model_index);
  } else {
    CompleteAnimationAndLayout();
  }

  return tab_ptr;
}

Because of that our vertical tab strip doesn't re-layout when first tab is added to any tab containers.
So, we have other buggy scenario mentioned above(#43656 (comment)).

To fix it, trying to give noti in that situation like below. but it gets another startup crashing.
If there is one initial tab, startup goes well and below this issue is fixed.

Tab* BraveTabContainer::AddTab(std::unique_ptr<Tab> tab,
                               int model_index,
                               TabPinned pinned) {
  Tab* new_tab = TabContainerImpl::AddTab(std::move(tab), model_index, pinned);
  if (GetWidget() && GetWidget()->IsVisible() && GetVisible() &&
      GetTabCount() == 1) {
    PreferredSizeChanged();
  }
  return new_tab;
}

[kjozwiak]

The above requires 1.75.175 or higher for 1.75.x verification 👍

[GeetaSarvadnya]

Verification PASSED on

Brave | 1.75.175 Chromium: 133.0.6943.54 (Official Build) (64-bit)
-- | --
Revision | 8e82be95a27b2e442e0099307c0c8ad6d12adcf0
OS | Windows 10 Version 22H2 (Build 19045.5440)

• Reproduced the issue on 1.75.174 Chromium: 133.0.6943.54 
• Verified the STR from the description on 1.75.175 Chromium: 133.0.6943.54 and ensured that click on new tab + opens up the new tab vertical tab bar when all the tabs are pinned.

• Verified the cases from New tab not opened if a New Tab button is clicked at the first instance when only pinned tabs are available in vertical tab view #43656 (comment)

Cases_PASSED

STR 1.

1. Turn on vertical tab mode
2. Open one window(A) and make it have one unpinned tab
3. Open another window(B) and make it have one pinned tab
4. Move window B's pinned tab to window A via pinned tab's context menu (Move tab to another window)
5. window B's pinned tab is moved to window A but it's not visible in window A

Confirmed that Pinned tab from Window B moved to Window A is shown on Windows A

STR2.

1. Turn on vertical tab mode
2. Open one window(A) and make it have one unpinned tab
3. Open another window(B) and make it have one pinned tab
4. Move window A's unpinned tab to window B via pinned tab's context menu (Move tab to another window)
5. window A's unpinned tab is moved to window B but it's not visible in window B

Confirmed that unpinned tab from window A is visible in window B