visible_when=False in Vgroup Tabbed still visible

[fred4ets]

Hi there,

I'm facing the following issue.

If i set 2 traits items and set one of them to be not visible, it is stil visible.

I join a CME to be more explicit : Tab #1 should be not visible.

What am I doing wrong?

Thanks in advance.

Regards

PS : Debian 10 x86_64 / Python 3.7.3, with Traits libs from git source (Traits 6.1.0 dev1414 & TraitsUI 6.2.0 dev123)

#! /usr/bin/env python3

from traits.api import Int, Float, HasTraits
from traitsui.api import (Group, HGroup, Item, Tabbed, VGroup, View)

class Foo(HasTraits):

    a = Int
    b = Float

    view = View(Tabbed(VGroup(HGroup(Item('a')),
                              label='Tab #1',
                              visible_when='False'),
                       VGroup(HGroup(Item('b')),
                              label='Tab #2',
                              visible_when='True')))

if (__name__ == '__main__'):
    foo = Foo()
    foo.configure_traits()

[fred4ets]

Hello,

Any news about this issue?

Ok, I fix a few typo:

#! /usr/bin/env python3

from traits.api import Int, Float, HasTraits
from traitsui.api import (Group, HGroup, Item, Tabbed, VGroup, View)

class Foo(HasTraits):

    a = Int
    b = Float
    
    view = View(Tabbed(VGroup(HGroup(Item('a')),
                              label='Tab #1',
                              visible_when='False'),
                       VGroup(HGroup(Item('b')),
                              label='Tab #2',
                       visible_when='True')))

if (__name__ == '__main__'):
    foo = Foo()
    foo.configure_traits()
    

PS: It works fine with wx, this is only with qt4 I have this issue.

[rahulporuri]

@fred4ets thanks for providing a way to reproduce the issue. I can reproduce this issue on windows + python 3.6 + pyqt5 5.14.2 and qt 5.12.6

[aaronayres35]

This appears to be relevant:
https://doc.qt.io/qt-5/qtabwidget.html#setTabVisible
but is new in Qt 5.15
It seems the old way of hiding / showing tabs is to entirely remove the tab while keeping a ref to it / its index, and then adding it back later with the https://doc.qt.io/qt-5/qtabwidget.html#removeTab and https://doc.qt.io/qt-5/qtabwidget.html#addTab methods

Also, I believe relevant traitsUI code is:

traitsui/traitsui/qt4/ui_panel.py

Lines 572 to 595 in 20f73e8

	elif group.layout in ("tabbed", "fold"):
	# Create the TabWidget or ToolBox.
	if group.layout == "tabbed":
	sub = QtGui.QTabWidget()
	else:
	sub = QtGui.QToolBox()
	# Give tab/tool widget stretch factor equivalent to default stretch
	# factory for a resizeable item. See end of '_add_items'.
	policy = sub.sizePolicy()
	policy.setHorizontalStretch(50)
	policy.setVerticalStretch(50)
	sub.setSizePolicy(policy)
	_fill_panel(sub, content, self.ui, self._add_page_item)
	if outer is None:
	outer = sub
	else:
	inner.addWidget(sub)
	# Create an editor.
	editor = TabbedFoldGroupEditor(container=sub, control=outer, ui=ui)
	self._setup_editor(group, editor)

and specifically _fill_panel:

traitsui/traitsui/qt4/ui_panel.py

Lines 296 to 344 in 20f73e8

	def _fill_panel(panel, content, ui, item_handler=None):
	"""Fill a page based container panel with content.
	"""
	active = 0
	for index, item in enumerate(content):
	page_name = item.get_label(ui)
	if page_name == "":
	page_name = "Page %d" % index
	if isinstance(item, Group):
	if item.selected:
	active = index
	gp = _GroupPanel(item, ui, suppress_label=True)
	page = gp.control
	sub_page = gp.sub_control
	# If the result is the same type with only one page, collapse it
	# down into just the page.
	if isinstance(sub_page, type(panel)) and sub_page.count() == 1:
	new = sub_page.widget(0)
	if isinstance(panel, QtGui.QTabWidget):
	sub_page.removeTab(0)
	else:
	sub_page.removeItem(0)
	elif isinstance(page, QtGui.QWidget):
	new = page
	else:
	new = QtGui.QWidget()
	new.setLayout(page)
	layout = new.layout()
	if layout is not None:
	layout.setAlignment(QtCore.Qt.AlignLeft | QtCore.Qt.AlignTop)
	else:
	new = QtGui.QWidget()
	layout = QtGui.QVBoxLayout(new)
	layout.setContentsMargins(0, 0, 0, 0)
	item_handler(item, layout)
	# Add the content.
	if isinstance(panel, QtGui.QTabWidget):
	panel.addTab(new, page_name)
	else:
	panel.addItem(new, page_name)
	panel.setCurrentIndex(active)

Doing some debugging, I am seeing that the UI is getting the visible_when string added to _visible with an appropriate corresponding GroupEditor... I also verified that even if cond_value is False here:

traitsui/traitsui/ui.py

Line 800 in 20f73e8

cond_value = eval(when, globals(), context)

the tab remains visible.

It seems to me the TabbedFoldGroupEditor or its container which is a QTabWidget needs to be responsible for seeing if any of the wrapped GroupEditors have visible == False, and update accordingly.

Unfortunately, we don't end up keeping track of the wrapped GroupEditor for the tab:

traitsui/traitsui/qt4/ui_panel.py

Line 627 in 20f73e8

self._setup_editor(group, GroupEditor(control=outer))

(although a reference to it is kept in the _visible list on the UI). This makes it tricky, as I don't know who should be charged with listening to when {add/remove}Tab should be called...

In summary I don't think this is a simple quick fix 😞 but I will see if I can get something working

[aaronayres35]

Also, when you first launch the tab is empty (as we correctly listen to visible_when):

but the tab itself is still visible even if its contents aren't and that is what we really want to not be visible. Also, clicking to the other tab and back, the content of tab 1 is then visible and will never become not visible again.

TThere is a disconnect between what traitsUI is trying to do and Qt below.