The
toolbar contains all tools, which can be used for editing a layer
with the mouse. The exact description of the tools can be found in
the chapter 6 of this manual. The tools with the red dot are multiple
used. By clicking and holding the mouse button, a popup appears
showing several tools. Now you can select one of them. The
selected tool will be shown in the toolbar afterwards.
There are not always the same tools in the toolbar. The available tools depend on the kind of the selected layer. If the selected layer is an image layer, different tools are used compared to a text layer. If you are missing a tool that should be available, you have probably selected the wrong layer.
All kind of tools have tool settings (see chapter 4.6). You should always have the tool settings on screen.
If the active layer is an image layer, the toolbar contains not only tools, but basic settings for the tools, too. These settings are: the foreground and background color, the current brush and mask editing settings.