As in many other areas, air traffic control has faced challenges in the reality of digitalization and automation. Despite the introduction of new technology, runway incursions are a persisting problem at airports. A runway incursion that develops into an incident or accident is the No 1 risk for the Air Navigation Service Providers. World-wide ATM tower work relies on variations of a generic design and tool set with a high degree of similarities, but with varying degrees of digitalization. Our study investigates the roles of ATM systems in the development of runway incursions, and on the potential to address them through further digitalization. This case study is based on the digitalized tower environment of Arlanda airport, and has a special focus on the electronic flight strips. Six episodes from a human-in-the loop simulation of Arlanda tower are described in detail, based on audio/video and eye gaze recordings. Four of the episodes contained irregularities of which two were runway incursions. Results showed that the e-strip system conceptually still very much plays the same role as the old paper strips it replaced, not taking full advantage of the possibilities of a digitalized system. It also showed that the systems in the tower environment are often not sharing information and that the human operator is very much left alone to gather and interpret the information from the different systems. The conclusion is that there are some significant design challenges ahead for to create the ATM system for the future with maintained or increased safety and performance with improved human-automation collaboration.