Tabs on the Modeling Canvas
It should be clear which tab is active, and which are not. The active tab should be brigher in colors and have more contrast from the tabs behind it. This can be enhanced by adding an additional visual flourish, such as the teal colored accent shown below.
Styling and Colors
Spacing Within a Tab
Alignment and top corner radius
Spacing between multiple tabs
Use consistent spacing between tabs.
Tabs in Tools Panels
It should be clear which tab is active, and which are not. The active tab should be brigher in colors and have more contrast from the tabs behind it.
Spacing
Active Vs Inactive
Tabs in Validation Panel
The validation panel at the bottom of the canvas doesn't have a default tab selected. There should be a visual indicator on hover that highlights the tab that will be selected. Upon selection, that highlight color should extend to the rest of the selected panel.