TopAppBar not adjusting height automatically in Compose and TabRow not working

Basically, I have two composable funcs which create a TopAppBar and add a tab layout contained in the app bar :

@Composable
fun ZCryptAppBar(
    modifier: Modifier = Modifier,
    title: @Composable RowScope.() -> Unit
) {
    Column(Modifier.fillMaxWidth()) {
        TopAppBar(
            title = {
                Column {
                    Row { title() }
                    Row {
                        TabLayout()
                    }
                }
            },
            modifier = modifier,
            backgroundColor = MaterialTheme.colors.primary,
            contentColor = Color.White
        )
    }
}

@Composable
fun TabLayout() {
    var selectedTab by remember {
        mutableStateOf(0)
    }
    TabRow(
        modifier = Modifier.fillMaxWidth(),
        selectedTabIndex = selectedTab,
        backgroundColor = MaterialTheme.colors.primary,
        tabs = {
            Tab(
                selected = selectedTab == 0,
                onClick = { selectedTab = 0 },
                text = { Text(stringResource(R.string.encrypt)) },
                icon = {
                    Image(
                        painterResource(id = R.drawable.ic_padlock_black),
                        stringResource(R.string.descr_icon_padlock)
                    )
                }
            )
            Tab(
                selected = selectedTab == 0,
                onClick = { selectedTab = 0 },
                text = { Text(stringResource(R.string.decrypt)) },
                icon = {
                    Image(
                        painterResource(id = R.drawable.ic_padunlock_black),
                        stringResource(R.string.descr_icon_padunlock)
                    )
                }
            )
        }
    )
}

But I am having two problems here : firstly, when I click on a tab, nothing happens and app stays in the same tab.

Secondly, the TopAppBar seems to not automatically adjust its height since the tab name and icon are all cropped :

The TopAppBar implements the Material design specs and has a fixed height of 56.dp.

You can use:

Column(Modifier.fillMaxWidth()) {
    TopAppBar(
        title = {
            Column() {
                Row { Text("Title") }
            }
        },
        backgroundColor = MaterialTheme.colors.primary,
        contentColor = Color.White
    )
    TabLayout()
}

Then in your TabLayout use:

       Tab(
            selected = selectedTab == 0,
            onClick = { selectedTab = 0 },
            //.....
        )
        Tab(
            selected = selectedTab == 1,
            onClick = { selectedTab = 1 },
            //.....
        )