Step 1: Understanding the description.
The poet mentions that the sadness "lurks near the open window there," which suggests that sadness is present in the environment surrounding the poet. The use of the word "lurks" implies that it is hidden or lurking in the background, perhaps unnoticed but ever-present.
Step 2: Interpretation of the setting.
The sadness is personified as something that waits near the window, as if it is waiting for something or someone. This makes it feel almost like a shadow, silently affecting the poet's emotional state.
Step 3: Conclusion.
Thus, the sadness lurks near the open window, possibly symbolizing the poet's vulnerability or the overwhelming feelings that can't be escaped.
Final Answer: \[ \boxed{\text{The sadness lurks near the open window, symbolizing a lingering sense of despair.}} \]